Executable: Move most rodata sections into the main rodata segment
[glibc/nacl-glibc.git] / elf / rtld.c
blobcb70ee43747f0fe7e32ca5eda124ffd78cd99abb
1 /* Run time dynamic linker.
2 Copyright (C) 1995-2006, 2007, 2008 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
20 #include <errno.h>
21 #include <dlfcn.h>
22 #include <fcntl.h>
23 #include <stdbool.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <unistd.h>
27 #include <sys/mman.h> /* Check if MAP_ANON is defined. */
28 #include <sys/param.h>
29 #include <sys/stat.h>
30 #include <ldsodefs.h>
31 #include <stdio-common/_itoa.h>
32 #include <entry.h>
33 #include <fpu_control.h>
34 #include <hp-timing.h>
35 #include <bits/libc-lock.h>
36 #include "dynamic-link.h"
37 #include <dl-librecon.h>
38 #include <unsecvars.h>
39 #include <dl-cache.h>
40 #include <dl-osinfo.h>
41 #include <dl-procinfo.h>
42 #include <tls.h>
44 #include <assert.h>
46 /* Avoid PLT use for our local calls at startup. */
47 extern __typeof (__mempcpy) __mempcpy attribute_hidden;
49 /* GCC has mental blocks about _exit. */
50 extern __typeof (_exit) exit_internal asm ("_exit") attribute_hidden;
51 #define _exit exit_internal
53 /* Helper function to handle errors while resolving symbols. */
54 static void print_unresolved (int errcode, const char *objname,
55 const char *errsting);
57 /* Helper function to handle errors when a version is missing. */
58 static void print_missing_version (int errcode, const char *objname,
59 const char *errsting);
61 /* Print the various times we collected. */
62 static void print_statistics (hp_timing_t *total_timep);
64 /* Add audit objects. */
65 static void process_dl_audit (char *str);
67 /* This is a list of all the modes the dynamic loader can be in. */
68 enum mode { normal, list, verify, trace };
70 /* Process all environments variables the dynamic linker must recognize.
71 Since all of them start with `LD_' we are a bit smarter while finding
72 all the entries. */
73 static void process_envvars (enum mode *modep);
75 #ifdef DL_ARGV_NOT_RELRO
76 int _dl_argc attribute_hidden;
77 char **_dl_argv = NULL;
78 /* Nonzero if we were run directly. */
79 unsigned int _dl_skip_args attribute_hidden;
80 #else
81 int _dl_argc attribute_relro attribute_hidden;
82 char **_dl_argv attribute_relro = NULL;
83 unsigned int _dl_skip_args attribute_relro attribute_hidden;
84 #endif
85 INTDEF(_dl_argv)
87 #ifndef THREAD_SET_STACK_GUARD
88 /* Only exported for architectures that don't store the stack guard canary
89 in thread local area. */
90 uintptr_t __stack_chk_guard attribute_relro;
91 #endif
93 /* Only exported for architectures that don't store the pointer guard
94 value in thread local area. */
95 uintptr_t __pointer_chk_guard_local
96 attribute_relro attribute_hidden __attribute__ ((nocommon));
97 #ifndef THREAD_SET_POINTER_GUARD
98 strong_alias (__pointer_chk_guard_local, __pointer_chk_guard)
99 #endif
102 /* List of auditing DSOs. */
103 static struct audit_list
105 const char *name;
106 struct audit_list *next;
107 } *audit_list;
109 #ifndef HAVE_INLINED_SYSCALLS
110 /* Set nonzero during loading and initialization of executable and
111 libraries, cleared before the executable's entry point runs. This
112 must not be initialized to nonzero, because the unused dynamic
113 linker loaded in for libc.so's "ld.so.1" dep will provide the
114 definition seen by libc.so's initializer; that value must be zero,
115 and will be since that dynamic linker's _dl_start and dl_main will
116 never be called. */
117 int _dl_starting_up = 0;
118 INTVARDEF(_dl_starting_up)
119 #endif
121 /* This is the structure which defines all variables global to ld.so
122 (except those which cannot be added for some reason). */
123 struct rtld_global _rtld_global =
125 /* Default presumption without further information is executable stack. */
126 ._dl_stack_flags = PF_R|PF_W|PF_X,
127 #ifdef _LIBC_REENTRANT
128 ._dl_load_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER
129 #endif
131 /* If we would use strong_alias here the compiler would see a
132 non-hidden definition. This would undo the effect of the previous
133 declaration. So spell out was strong_alias does plus add the
134 visibility attribute. */
135 extern struct rtld_global _rtld_local
136 __attribute__ ((alias ("_rtld_global"), visibility ("hidden")));
139 /* This variable is similar to _rtld_local, but all values are
140 read-only after relocation. */
141 struct rtld_global_ro _rtld_global_ro attribute_relro =
143 /* Get architecture specific initializer. */
144 #include <dl-procinfo.c>
145 #ifdef NEED_DL_SYSINFO
146 ._dl_sysinfo = DL_SYSINFO_DEFAULT,
147 #endif
148 ._dl_debug_fd = STDERR_FILENO,
149 ._dl_use_load_bias = -2,
150 ._dl_correct_cache_id = _DL_CACHE_DEFAULT_ID,
151 ._dl_hwcap_mask = HWCAP_IMPORTANT,
152 ._dl_lazy = 1,
153 ._dl_fpu_control = _FPU_DEFAULT,
154 ._dl_pointer_guard = 1,
156 /* Function pointers. */
157 ._dl_debug_printf = _dl_debug_printf,
158 ._dl_catch_error = _dl_catch_error,
159 ._dl_signal_error = _dl_signal_error,
160 ._dl_mcount = _dl_mcount_internal,
161 ._dl_lookup_symbol_x = _dl_lookup_symbol_x,
162 ._dl_check_caller = _dl_check_caller,
163 ._dl_open = _dl_open,
164 ._dl_close = _dl_close,
165 ._dl_tls_get_addr_soft = _dl_tls_get_addr_soft,
166 #ifdef HAVE_DL_DISCOVER_OSVERSION
167 ._dl_discover_osversion = _dl_discover_osversion
168 #endif
170 /* If we would use strong_alias here the compiler would see a
171 non-hidden definition. This would undo the effect of the previous
172 declaration. So spell out was strong_alias does plus add the
173 visibility attribute. */
174 extern struct rtld_global_ro _rtld_local_ro
175 __attribute__ ((alias ("_rtld_global_ro"), visibility ("hidden")));
178 static void dl_main (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
179 ElfW(Addr) *user_entry);
181 /* These two variables cannot be moved into .data.rel.ro. */
182 static struct libname_list _dl_rtld_libname;
183 static struct libname_list _dl_rtld_libname2;
185 /* We expect less than a second for relocation. */
186 #ifdef HP_SMALL_TIMING_AVAIL
187 # undef HP_TIMING_AVAIL
188 # define HP_TIMING_AVAIL HP_SMALL_TIMING_AVAIL
189 #endif
191 /* Variable for statistics. */
192 #ifndef HP_TIMING_NONAVAIL
193 static hp_timing_t relocate_time;
194 static hp_timing_t load_time attribute_relro;
195 static hp_timing_t start_time attribute_relro;
196 #endif
198 /* Additional definitions needed by TLS initialization. */
199 #ifdef TLS_INIT_HELPER
200 TLS_INIT_HELPER
201 #endif
203 /* Helper function for syscall implementation. */
204 #ifdef DL_SYSINFO_IMPLEMENTATION
205 DL_SYSINFO_IMPLEMENTATION
206 #endif
208 /* Before ld.so is relocated we must not access variables which need
209 relocations. This means variables which are exported. Variables
210 declared as static are fine. If we can mark a variable hidden this
211 is fine, too. The latter is important here. We can avoid setting
212 up a temporary link map for ld.so if we can mark _rtld_global as
213 hidden. */
214 #ifdef PI_STATIC_AND_HIDDEN
215 # define DONT_USE_BOOTSTRAP_MAP 1
216 #endif
218 #ifdef DONT_USE_BOOTSTRAP_MAP
219 static ElfW(Addr) _dl_start_final (void *arg);
220 #else
221 struct dl_start_final_info
223 struct link_map l;
224 #if !defined HP_TIMING_NONAVAIL && HP_TIMING_INLINE
225 hp_timing_t start_time;
226 #endif
228 static ElfW(Addr) _dl_start_final (void *arg,
229 struct dl_start_final_info *info);
230 #endif
232 /* These defined magically in the linker script. */
233 extern char _begin[] attribute_hidden;
234 extern char _etext[] attribute_hidden;
235 extern char _end[] attribute_hidden;
238 #ifdef RTLD_START
239 RTLD_START
240 #else
241 # error "sysdeps/MACHINE/dl-machine.h fails to define RTLD_START"
242 #endif
244 #ifndef VALIDX
245 # define VALIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
246 + DT_EXTRANUM + DT_VALTAGIDX (tag))
247 #endif
248 #ifndef ADDRIDX
249 # define ADDRIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
250 + DT_EXTRANUM + DT_VALNUM + DT_ADDRTAGIDX (tag))
251 #endif
253 /* This is the second half of _dl_start (below). It can be inlined safely
254 under DONT_USE_BOOTSTRAP_MAP, where it is careful not to make any GOT
255 references. When the tools don't permit us to avoid using a GOT entry
256 for _dl_rtld_global (no attribute_hidden support), we must make sure
257 this function is not inlined (see below). */
259 #ifdef DONT_USE_BOOTSTRAP_MAP
260 static inline ElfW(Addr) __attribute__ ((always_inline))
261 _dl_start_final (void *arg)
262 #else
263 static ElfW(Addr) __attribute__ ((noinline))
264 _dl_start_final (void *arg, struct dl_start_final_info *info)
265 #endif
267 ElfW(Addr) start_addr;
269 if (HP_TIMING_AVAIL)
271 /* If it hasn't happen yet record the startup time. */
272 if (! HP_TIMING_INLINE)
273 HP_TIMING_NOW (start_time);
274 #if !defined DONT_USE_BOOTSTRAP_MAP && !defined HP_TIMING_NONAVAIL
275 else
276 start_time = info->start_time;
277 #endif
279 /* Initialize the timing functions. */
280 HP_TIMING_DIFF_INIT ();
283 /* Transfer data about ourselves to the permanent link_map structure. */
284 #ifndef DONT_USE_BOOTSTRAP_MAP
285 GL(dl_rtld_map).l_addr = info->l.l_addr;
286 GL(dl_rtld_map).l_ld = info->l.l_ld;
287 memcpy (GL(dl_rtld_map).l_info, info->l.l_info,
288 sizeof GL(dl_rtld_map).l_info);
289 GL(dl_rtld_map).l_mach = info->l.l_mach;
290 GL(dl_rtld_map).l_relocated = 1;
291 #endif
292 _dl_setup_hash (&GL(dl_rtld_map));
293 GL(dl_rtld_map).l_real = &GL(dl_rtld_map);
294 GL(dl_rtld_map).l_map_start = (ElfW(Addr)) _begin;
295 GL(dl_rtld_map).l_map_end = (ElfW(Addr)) _end;
296 GL(dl_rtld_map).l_text_end = (ElfW(Addr)) _etext;
297 /* Copy the TLS related data if necessary. */
298 #ifndef DONT_USE_BOOTSTRAP_MAP
299 # if USE___THREAD
300 assert (info->l.l_tls_modid != 0);
301 GL(dl_rtld_map).l_tls_blocksize = info->l.l_tls_blocksize;
302 GL(dl_rtld_map).l_tls_align = info->l.l_tls_align;
303 GL(dl_rtld_map).l_tls_firstbyte_offset = info->l.l_tls_firstbyte_offset;
304 GL(dl_rtld_map).l_tls_initimage_size = info->l.l_tls_initimage_size;
305 GL(dl_rtld_map).l_tls_initimage = info->l.l_tls_initimage;
306 GL(dl_rtld_map).l_tls_offset = info->l.l_tls_offset;
307 GL(dl_rtld_map).l_tls_modid = 1;
308 # else
309 # if NO_TLS_OFFSET != 0
310 GL(dl_rtld_map).l_tls_offset = NO_TLS_OFFSET;
311 # endif
312 # endif
314 #endif
316 #if HP_TIMING_AVAIL
317 HP_TIMING_NOW (GL(dl_cpuclock_offset));
318 #endif
320 /* Initialize the stack end variable. */
321 __libc_stack_end = __builtin_frame_address (0);
323 /* Call the OS-dependent function to set up life so we can do things like
324 file access. It will call `dl_main' (below) to do all the real work
325 of the dynamic linker, and then unwind our frame and run the user
326 entry point on the same stack we entered on. */
327 start_addr = _dl_sysdep_start (arg, &dl_main);
329 #ifndef HP_TIMING_NONAVAIL
330 hp_timing_t rtld_total_time;
331 if (HP_TIMING_AVAIL)
333 hp_timing_t end_time;
335 /* Get the current time. */
336 HP_TIMING_NOW (end_time);
338 /* Compute the difference. */
339 HP_TIMING_DIFF (rtld_total_time, start_time, end_time);
341 #endif
343 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_STATISTICS, 0))
345 #ifndef HP_TIMING_NONAVAIL
346 print_statistics (&rtld_total_time);
347 #else
348 print_statistics (NULL);
349 #endif
352 return start_addr;
355 static ElfW(Addr) __attribute_used__ internal_function
356 __attribute__ ((regparm (3), stdcall))
357 _dl_start (void *arg)
359 #ifdef DONT_USE_BOOTSTRAP_MAP
360 # define bootstrap_map GL(dl_rtld_map)
361 #else
362 struct dl_start_final_info info;
363 # define bootstrap_map info.l
364 #endif
366 /* This #define produces dynamic linking inline functions for
367 bootstrap relocation instead of general-purpose relocation.
368 Since ld.so must not have any undefined symbols the result
369 is trivial: always the map of ld.so itself. */
370 #define RTLD_BOOTSTRAP
371 #define RESOLVE_MAP(sym, version, flags) (&bootstrap_map)
372 #include "dynamic-link.h"
374 if (HP_TIMING_INLINE && HP_TIMING_AVAIL)
375 #ifdef DONT_USE_BOOTSTRAP_MAP
376 HP_TIMING_NOW (start_time);
377 #else
378 HP_TIMING_NOW (info.start_time);
379 #endif
381 /* Partly clean the `bootstrap_map' structure up. Don't use
382 `memset' since it might not be built in or inlined and we cannot
383 make function calls at this point. Use '__builtin_memset' if we
384 know it is available. We do not have to clear the memory if we
385 do not have to use the temporary bootstrap_map. Global variables
386 are initialized to zero by default. */
387 #ifndef DONT_USE_BOOTSTRAP_MAP
388 # ifdef HAVE_BUILTIN_MEMSET
389 __builtin_memset (bootstrap_map.l_info, '\0', sizeof (bootstrap_map.l_info));
390 # else
391 for (size_t cnt = 0;
392 cnt < sizeof (bootstrap_map.l_info) / sizeof (bootstrap_map.l_info[0]);
393 ++cnt)
394 bootstrap_map.l_info[cnt] = 0;
395 # endif
396 # if USE___THREAD
397 bootstrap_map.l_tls_modid = 0;
398 # endif
399 #endif
401 /* Figure out the run-time load address of the dynamic linker itself. */
402 bootstrap_map.l_addr = elf_machine_load_address ();
404 /* Read our own dynamic section and fill in the info array. */
405 bootstrap_map.l_ld = (void *) bootstrap_map.l_addr + elf_machine_dynamic ();
406 elf_get_dynamic_info (&bootstrap_map, NULL);
408 #if NO_TLS_OFFSET != 0
409 bootstrap_map.l_tls_offset = NO_TLS_OFFSET;
410 #endif
412 /* Get the dynamic linker's own program header. First we need the ELF
413 file header. The `_begin' symbol created by the linker script points
414 to it. When we have something like GOTOFF relocs, we can use a plain
415 reference to find the runtime address. Without that, we have to rely
416 on the `l_addr' value, which is not the value we want when prelinked. */
417 #if USE___THREAD
418 dtv_t initdtv[3];
419 ElfW(Ehdr) *ehdr
420 # ifdef DONT_USE_BOOTSTRAP_MAP
421 = (ElfW(Ehdr) *) &_begin;
422 # else
423 # error This will not work with prelink.
424 = (ElfW(Ehdr) *) bootstrap_map.l_addr;
425 # endif
426 ElfW(Phdr) *phdr = (ElfW(Phdr) *) ((void *) ehdr + ehdr->e_phoff);
427 size_t cnt = ehdr->e_phnum; /* PT_TLS is usually the last phdr. */
428 while (cnt-- > 0)
429 if (phdr[cnt].p_type == PT_TLS)
431 void *tlsblock;
432 size_t max_align = MAX (TLS_INIT_TCB_ALIGN, phdr[cnt].p_align);
433 char *p;
435 bootstrap_map.l_tls_blocksize = phdr[cnt].p_memsz;
436 bootstrap_map.l_tls_align = phdr[cnt].p_align;
437 if (phdr[cnt].p_align == 0)
438 bootstrap_map.l_tls_firstbyte_offset = 0;
439 else
440 bootstrap_map.l_tls_firstbyte_offset = (phdr[cnt].p_vaddr
441 & (phdr[cnt].p_align - 1));
442 assert (bootstrap_map.l_tls_blocksize != 0);
443 bootstrap_map.l_tls_initimage_size = phdr[cnt].p_filesz;
444 bootstrap_map.l_tls_initimage = (void *) (bootstrap_map.l_addr
445 + phdr[cnt].p_vaddr);
447 /* We can now allocate the initial TLS block. This can happen
448 on the stack. We'll get the final memory later when we
449 know all about the various objects loaded at startup
450 time. */
451 # if TLS_TCB_AT_TP
452 tlsblock = alloca (roundup (bootstrap_map.l_tls_blocksize,
453 TLS_INIT_TCB_ALIGN)
454 + TLS_INIT_TCB_SIZE
455 + max_align);
456 # elif TLS_DTV_AT_TP
457 tlsblock = alloca (roundup (TLS_INIT_TCB_SIZE,
458 bootstrap_map.l_tls_align)
459 + bootstrap_map.l_tls_blocksize
460 + max_align);
461 # else
462 /* In case a model with a different layout for the TCB and DTV
463 is defined add another #elif here and in the following #ifs. */
464 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
465 # endif
466 /* Align the TLS block. */
467 tlsblock = (void *) (((uintptr_t) tlsblock + max_align - 1)
468 & ~(max_align - 1));
470 /* Initialize the dtv. [0] is the length, [1] the generation
471 counter. */
472 initdtv[0].counter = 1;
473 initdtv[1].counter = 0;
475 /* Initialize the TLS block. */
476 # if TLS_TCB_AT_TP
477 initdtv[2].pointer = tlsblock;
478 # elif TLS_DTV_AT_TP
479 bootstrap_map.l_tls_offset = roundup (TLS_INIT_TCB_SIZE,
480 bootstrap_map.l_tls_align);
481 initdtv[2].pointer = (char *) tlsblock + bootstrap_map.l_tls_offset;
482 # else
483 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
484 # endif
485 p = __mempcpy (initdtv[2].pointer, bootstrap_map.l_tls_initimage,
486 bootstrap_map.l_tls_initimage_size);
487 # ifdef HAVE_BUILTIN_MEMSET
488 __builtin_memset (p, '\0', (bootstrap_map.l_tls_blocksize
489 - bootstrap_map.l_tls_initimage_size));
490 # else
492 size_t remaining = (bootstrap_map.l_tls_blocksize
493 - bootstrap_map.l_tls_initimage_size);
494 while (remaining-- > 0)
495 *p++ = '\0';
497 # endif
499 /* Install the pointer to the dtv. */
501 /* Initialize the thread pointer. */
502 # if TLS_TCB_AT_TP
503 bootstrap_map.l_tls_offset
504 = roundup (bootstrap_map.l_tls_blocksize, TLS_INIT_TCB_ALIGN);
506 INSTALL_DTV ((char *) tlsblock + bootstrap_map.l_tls_offset,
507 initdtv);
509 const char *lossage = TLS_INIT_TP ((char *) tlsblock
510 + bootstrap_map.l_tls_offset, 0);
511 # elif TLS_DTV_AT_TP
512 INSTALL_DTV (tlsblock, initdtv);
513 const char *lossage = TLS_INIT_TP (tlsblock, 0);
514 # else
515 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
516 # endif
517 if (__builtin_expect (lossage != NULL, 0))
518 _dl_fatal_printf ("cannot set up thread-local storage: %s\n",
519 lossage);
521 /* So far this is module number one. */
522 bootstrap_map.l_tls_modid = 1;
524 /* There can only be one PT_TLS entry. */
525 break;
527 #endif /* USE___THREAD */
529 #ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
530 ELF_MACHINE_BEFORE_RTLD_RELOC (bootstrap_map.l_info);
531 #endif
533 if (bootstrap_map.l_addr || ! bootstrap_map.l_info[VALIDX(DT_GNU_PRELINKED)])
535 /* Relocate ourselves so we can do normal function calls and
536 data access using the global offset table. */
538 ELF_DYNAMIC_RELOCATE (&bootstrap_map, 0, 0);
540 bootstrap_map.l_relocated = 1;
542 /* Please note that we don't allow profiling of this object and
543 therefore need not test whether we have to allocate the array
544 for the relocation results (as done in dl-reloc.c). */
546 /* Now life is sane; we can call functions and access global data.
547 Set up to use the operating system facilities, and find out from
548 the operating system's program loader where to find the program
549 header table in core. Put the rest of _dl_start into a separate
550 function, that way the compiler cannot put accesses to the GOT
551 before ELF_DYNAMIC_RELOCATE. */
553 #ifdef DONT_USE_BOOTSTRAP_MAP
554 ElfW(Addr) entry = _dl_start_final (arg);
555 #else
556 ElfW(Addr) entry = _dl_start_final (arg, &info);
557 #endif
559 #ifndef ELF_MACHINE_START_ADDRESS
560 # define ELF_MACHINE_START_ADDRESS(map, start) (start)
561 #endif
563 return ELF_MACHINE_START_ADDRESS (GL(dl_ns)[LM_ID_BASE]._ns_loaded, entry);
569 /* Now life is peachy; we can do all normal operations.
570 On to the real work. */
572 /* Some helper functions. */
574 /* Arguments to relocate_doit. */
575 struct relocate_args
577 struct link_map *l;
578 int lazy;
581 struct map_args
583 /* Argument to map_doit. */
584 char *str;
585 struct link_map *loader;
586 int is_preloaded;
587 int mode;
588 /* Return value of map_doit. */
589 struct link_map *map;
592 struct dlmopen_args
594 const char *fname;
595 struct link_map *map;
598 struct lookup_args
600 const char *name;
601 struct link_map *map;
602 void *result;
605 /* Arguments to version_check_doit. */
606 struct version_check_args
608 int doexit;
609 int dotrace;
612 static void
613 relocate_doit (void *a)
615 struct relocate_args *args = (struct relocate_args *) a;
617 _dl_relocate_object (args->l, args->l->l_scope, args->lazy, 0);
620 static void
621 map_doit (void *a)
623 struct map_args *args = (struct map_args *) a;
624 args->map = _dl_map_object (args->loader, args->str,
625 args->is_preloaded, lt_library, 0, args->mode,
626 LM_ID_BASE);
629 static void
630 dlmopen_doit (void *a)
632 struct dlmopen_args *args = (struct dlmopen_args *) a;
633 args->map = _dl_open (args->fname, RTLD_LAZY | __RTLD_DLOPEN | __RTLD_AUDIT,
634 dl_main, LM_ID_NEWLM, _dl_argc, INTUSE(_dl_argv),
635 __environ);
638 static void
639 lookup_doit (void *a)
641 struct lookup_args *args = (struct lookup_args *) a;
642 const ElfW(Sym) *ref = NULL;
643 args->result = NULL;
644 lookup_t l = _dl_lookup_symbol_x (args->name, args->map, &ref,
645 args->map->l_local_scope, NULL, 0,
646 DL_LOOKUP_RETURN_NEWEST, NULL);
647 if (ref != NULL)
648 args->result = DL_SYMBOL_ADDRESS (l, ref);
651 static void
652 version_check_doit (void *a)
654 struct version_check_args *args = (struct version_check_args *) a;
655 if (_dl_check_all_versions (GL(dl_ns)[LM_ID_BASE]._ns_loaded, 1,
656 args->dotrace) && args->doexit)
657 /* We cannot start the application. Abort now. */
658 _exit (1);
662 static inline struct link_map *
663 find_needed (const char *name)
665 struct r_scope_elem *scope = &GL(dl_ns)[LM_ID_BASE]._ns_loaded->l_searchlist;
666 unsigned int n = scope->r_nlist;
668 while (n-- > 0)
669 if (_dl_name_match_p (name, scope->r_list[n]))
670 return scope->r_list[n];
672 /* Should never happen. */
673 return NULL;
676 static int
677 match_version (const char *string, struct link_map *map)
679 const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
680 ElfW(Verdef) *def;
682 #define VERDEFTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERDEF))
683 if (map->l_info[VERDEFTAG] == NULL)
684 /* The file has no symbol versioning. */
685 return 0;
687 def = (ElfW(Verdef) *) ((char *) map->l_addr
688 + map->l_info[VERDEFTAG]->d_un.d_ptr);
689 while (1)
691 ElfW(Verdaux) *aux = (ElfW(Verdaux) *) ((char *) def + def->vd_aux);
693 /* Compare the version strings. */
694 if (strcmp (string, strtab + aux->vda_name) == 0)
695 /* Bingo! */
696 return 1;
698 /* If no more definitions we failed to find what we want. */
699 if (def->vd_next == 0)
700 break;
702 /* Next definition. */
703 def = (ElfW(Verdef) *) ((char *) def + def->vd_next);
706 return 0;
709 static bool tls_init_tp_called;
711 static void *
712 init_tls (void)
714 /* Number of elements in the static TLS block. */
715 GL(dl_tls_static_nelem) = GL(dl_tls_max_dtv_idx);
717 /* Do not do this twice. The audit interface might have required
718 the DTV interfaces to be set up early. */
719 if (GL(dl_initial_dtv) != NULL)
720 return NULL;
722 /* Allocate the array which contains the information about the
723 dtv slots. We allocate a few entries more than needed to
724 avoid the need for reallocation. */
725 size_t nelem = GL(dl_tls_max_dtv_idx) + 1 + TLS_SLOTINFO_SURPLUS;
727 /* Allocate. */
728 GL(dl_tls_dtv_slotinfo_list) = (struct dtv_slotinfo_list *)
729 calloc (sizeof (struct dtv_slotinfo_list)
730 + nelem * sizeof (struct dtv_slotinfo), 1);
731 /* No need to check the return value. If memory allocation failed
732 the program would have been terminated. */
734 struct dtv_slotinfo *slotinfo = GL(dl_tls_dtv_slotinfo_list)->slotinfo;
735 GL(dl_tls_dtv_slotinfo_list)->len = nelem;
736 GL(dl_tls_dtv_slotinfo_list)->next = NULL;
738 /* Fill in the information from the loaded modules. No namespace
739 but the base one can be filled at this time. */
740 assert (GL(dl_ns)[LM_ID_BASE + 1]._ns_loaded == NULL);
741 int i = 0;
742 for (struct link_map *l = GL(dl_ns)[LM_ID_BASE]._ns_loaded; l != NULL;
743 l = l->l_next)
744 if (l->l_tls_blocksize != 0)
746 /* This is a module with TLS data. Store the map reference.
747 The generation counter is zero. */
748 slotinfo[i].map = l;
749 /* slotinfo[i].gen = 0; */
750 ++i;
752 assert (i == GL(dl_tls_max_dtv_idx));
754 /* Compute the TLS offsets for the various blocks. */
755 _dl_determine_tlsoffset ();
757 /* Construct the static TLS block and the dtv for the initial
758 thread. For some platforms this will include allocating memory
759 for the thread descriptor. The memory for the TLS block will
760 never be freed. It should be allocated accordingly. The dtv
761 array can be changed if dynamic loading requires it. */
762 void *tcbp = _dl_allocate_tls_storage ();
763 if (tcbp == NULL)
764 _dl_fatal_printf ("\
765 cannot allocate TLS data structures for initial thread");
767 /* Store for detection of the special case by __tls_get_addr
768 so it knows not to pass this dtv to the normal realloc. */
769 GL(dl_initial_dtv) = GET_DTV (tcbp);
771 /* And finally install it for the main thread. If ld.so itself uses
772 TLS we know the thread pointer was initialized earlier. */
773 const char *lossage = TLS_INIT_TP (tcbp, USE___THREAD);
774 if (__builtin_expect (lossage != NULL, 0))
775 _dl_fatal_printf ("cannot set up thread-local storage: %s\n", lossage);
776 tls_init_tp_called = true;
778 return tcbp;
781 #ifdef _LIBC_REENTRANT
782 /* _dl_error_catch_tsd points to this for the single-threaded case.
783 It's reset by the thread library for multithreaded programs. */
784 void ** __attribute__ ((const))
785 _dl_initial_error_catch_tsd (void)
787 static void *data;
788 return &data;
790 #endif
793 static unsigned int
794 do_preload (char *fname, struct link_map *main_map, const char *where)
796 const char *objname;
797 const char *err_str = NULL;
798 struct map_args args;
799 bool malloced;
801 args.str = fname;
802 args.loader = main_map;
803 args.is_preloaded = 1;
804 args.mode = 0;
806 unsigned int old_nloaded = GL(dl_ns)[LM_ID_BASE]._ns_nloaded;
808 (void) _dl_catch_error (&objname, &err_str, &malloced, map_doit, &args);
809 if (__builtin_expect (err_str != NULL, 0))
811 _dl_error_printf ("\
812 ERROR: ld.so: object '%s' from %s cannot be preloaded: ignored.\n",
813 fname, where);
814 /* No need to call free, this is still before
815 the libc's malloc is used. */
817 else if (GL(dl_ns)[LM_ID_BASE]._ns_nloaded != old_nloaded)
818 /* It is no duplicate. */
819 return 1;
821 /* Nothing loaded. */
822 return 0;
825 #if defined SHARED && defined _LIBC_REENTRANT \
826 && defined __rtld_lock_default_lock_recursive
827 static void
828 rtld_lock_default_lock_recursive (void *lock)
830 __rtld_lock_default_lock_recursive (lock);
833 static void
834 rtld_lock_default_unlock_recursive (void *lock)
836 __rtld_lock_default_unlock_recursive (lock);
838 #endif
841 static void
842 security_init (void)
844 /* Set up the stack checker's canary. */
845 uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard ();
846 #ifdef THREAD_SET_STACK_GUARD
847 THREAD_SET_STACK_GUARD (stack_chk_guard);
848 #else
849 __stack_chk_guard = stack_chk_guard;
850 #endif
852 /* Set up the pointer guard as well, if necessary. */
853 if (GLRO(dl_pointer_guard))
855 // XXX If it is cheap, we should use a separate value.
856 uintptr_t pointer_chk_guard = stack_chk_guard;
857 #ifndef HP_TIMING_NONAVAIL
858 hp_timing_t now;
859 HP_TIMING_NOW (now);
860 pointer_chk_guard ^= now;
861 #endif
862 #ifdef THREAD_SET_POINTER_GUARD
863 THREAD_SET_POINTER_GUARD (pointer_chk_guard);
864 #endif
865 __pointer_chk_guard_local = pointer_chk_guard;
870 /* The library search path. */
871 static const char *library_path attribute_relro;
872 /* The list preloaded objects. */
873 static const char *preloadlist attribute_relro;
874 /* Nonzero if information about versions has to be printed. */
875 static int version_info attribute_relro;
877 static void
878 dl_main (const ElfW(Phdr) *phdr,
879 ElfW(Word) phnum,
880 ElfW(Addr) *user_entry)
882 const ElfW(Phdr) *ph;
883 enum mode mode;
884 struct link_map *main_map;
885 size_t file_size;
886 char *file;
887 bool has_interp = false;
888 unsigned int i;
889 bool prelinked = false;
890 bool rtld_is_main = false;
891 #ifndef HP_TIMING_NONAVAIL
892 hp_timing_t start;
893 hp_timing_t stop;
894 hp_timing_t diff;
895 #endif
896 void *tcbp = NULL;
898 #ifdef _LIBC_REENTRANT
899 /* Explicit initialization since the reloc would just be more work. */
900 GL(dl_error_catch_tsd) = &_dl_initial_error_catch_tsd;
901 #endif
903 GL(dl_init_static_tls) = &_dl_nothread_init_static_tls;
905 #if defined SHARED && defined _LIBC_REENTRANT \
906 && defined __rtld_lock_default_lock_recursive
907 GL(dl_rtld_lock_recursive) = rtld_lock_default_lock_recursive;
908 GL(dl_rtld_unlock_recursive) = rtld_lock_default_unlock_recursive;
909 #endif
911 /* The explicit initialization here is cheaper than processing the reloc
912 in the _rtld_local definition's initializer. */
913 GL(dl_make_stack_executable_hook) = &_dl_make_stack_executable;
915 /* Process the environment variable which control the behaviour. */
916 process_envvars (&mode);
918 #ifndef HAVE_INLINED_SYSCALLS
919 /* Set up a flag which tells we are just starting. */
920 INTUSE(_dl_starting_up) = 1;
921 #endif
923 if (*user_entry == (ElfW(Addr)) ENTRY_POINT)
925 /* Ho ho. We are not the program interpreter! We are the program
926 itself! This means someone ran ld.so as a command. Well, that
927 might be convenient to do sometimes. We support it by
928 interpreting the args like this:
930 ld.so PROGRAM ARGS...
932 The first argument is the name of a file containing an ELF
933 executable we will load and run with the following arguments.
934 To simplify life here, PROGRAM is searched for using the
935 normal rules for shared objects, rather than $PATH or anything
936 like that. We just load it and use its entry point; we don't
937 pay attention to its PT_INTERP command (we are the interpreter
938 ourselves). This is an easy way to test a new ld.so before
939 installing it. */
940 rtld_is_main = true;
942 /* Note the place where the dynamic linker actually came from. */
943 GL(dl_rtld_map).l_name = rtld_progname;
945 while (_dl_argc > 1)
946 if (! strcmp (INTUSE(_dl_argv)[1], "--list"))
948 mode = list;
949 GLRO(dl_lazy) = -1; /* This means do no dependency analysis. */
951 ++_dl_skip_args;
952 --_dl_argc;
953 ++INTUSE(_dl_argv);
955 else if (! strcmp (INTUSE(_dl_argv)[1], "--verify"))
957 mode = verify;
959 ++_dl_skip_args;
960 --_dl_argc;
961 ++INTUSE(_dl_argv);
963 else if (! strcmp (INTUSE(_dl_argv)[1], "--library-path")
964 && _dl_argc > 2)
966 library_path = INTUSE(_dl_argv)[2];
968 _dl_skip_args += 2;
969 _dl_argc -= 2;
970 INTUSE(_dl_argv) += 2;
972 else if (! strcmp (INTUSE(_dl_argv)[1], "--inhibit-rpath")
973 && _dl_argc > 2)
975 GLRO(dl_inhibit_rpath) = INTUSE(_dl_argv)[2];
977 _dl_skip_args += 2;
978 _dl_argc -= 2;
979 INTUSE(_dl_argv) += 2;
981 else if (! strcmp (INTUSE(_dl_argv)[1], "--audit") && _dl_argc > 2)
983 process_dl_audit (INTUSE(_dl_argv)[2]);
985 _dl_skip_args += 2;
986 _dl_argc -= 2;
987 INTUSE(_dl_argv) += 2;
989 else
990 break;
992 /* If we have no further argument the program was called incorrectly.
993 Grant the user some education. */
994 if (_dl_argc < 2)
995 _dl_fatal_printf ("\
996 Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\
997 You have invoked `ld.so', the helper program for shared library executables.\n\
998 This program usually lives in the file `/lib/ld.so', and special directives\n\
999 in executable files using ELF shared libraries tell the system's program\n\
1000 loader to load the helper program from this file. This helper program loads\n\
1001 the shared libraries needed by the program executable, prepares the program\n\
1002 to run, and runs it. You may invoke this helper program directly from the\n\
1003 command line to load and run an ELF executable file; this is like executing\n\
1004 that file itself, but always uses this helper program from the file you\n\
1005 specified, instead of the helper program file specified in the executable\n\
1006 file you run. This is mostly of use for maintainers to test new versions\n\
1007 of this helper program; chances are you did not intend to run this program.\n\
1009 --list list all dependencies and how they are resolved\n\
1010 --verify verify that given object really is a dynamically linked\n\
1011 object we can handle\n\
1012 --library-path PATH use given PATH instead of content of the environment\n\
1013 variable LD_LIBRARY_PATH\n\
1014 --inhibit-rpath LIST ignore RUNPATH and RPATH information in object names\n\
1015 in LIST\n");
1017 ++_dl_skip_args;
1018 --_dl_argc;
1019 ++INTUSE(_dl_argv);
1021 /* The initialization of _dl_stack_flags done below assumes the
1022 executable's PT_GNU_STACK may have been honored by the kernel, and
1023 so a PT_GNU_STACK with PF_X set means the stack started out with
1024 execute permission. However, this is not really true if the
1025 dynamic linker is the executable the kernel loaded. For this
1026 case, we must reinitialize _dl_stack_flags to match the dynamic
1027 linker itself. If the dynamic linker was built with a
1028 PT_GNU_STACK, then the kernel may have loaded us with a
1029 nonexecutable stack that we will have to make executable when we
1030 load the program below unless it has a PT_GNU_STACK indicating
1031 nonexecutable stack is ok. */
1033 for (ph = phdr; ph < &phdr[phnum]; ++ph)
1034 if (ph->p_type == PT_GNU_STACK)
1036 GL(dl_stack_flags) = ph->p_flags;
1037 break;
1040 if (__builtin_expect (mode, normal) == verify)
1042 const char *objname;
1043 const char *err_str = NULL;
1044 struct map_args args;
1045 bool malloced;
1047 args.str = rtld_progname;
1048 args.loader = NULL;
1049 args.is_preloaded = 0;
1050 args.mode = __RTLD_OPENEXEC;
1051 (void) _dl_catch_error (&objname, &err_str, &malloced, map_doit,
1052 &args);
1053 if (__builtin_expect (err_str != NULL, 0))
1054 /* We don't free the returned string, the programs stops
1055 anyway. */
1056 _exit (EXIT_FAILURE);
1058 else
1060 HP_TIMING_NOW (start);
1061 _dl_map_object (NULL, rtld_progname, 0, lt_library, 0,
1062 __RTLD_OPENEXEC, LM_ID_BASE);
1063 HP_TIMING_NOW (stop);
1065 HP_TIMING_DIFF (load_time, start, stop);
1068 /* Now the map for the main executable is available. */
1069 main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
1071 phdr = main_map->l_phdr;
1072 phnum = main_map->l_phnum;
1073 /* We overwrite here a pointer to a malloc()ed string. But since
1074 the malloc() implementation used at this point is the dummy
1075 implementations which has no real free() function it does not
1076 makes sense to free the old string first. */
1077 main_map->l_name = (char *) "";
1078 *user_entry = main_map->l_entry;
1080 else
1082 /* Create a link_map for the executable itself.
1083 This will be what dlopen on "" returns. */
1084 main_map = _dl_new_object ((char *) "", "", lt_executable, NULL,
1085 __RTLD_OPENEXEC, LM_ID_BASE);
1086 assert (main_map != NULL);
1087 assert (main_map == GL(dl_ns)[LM_ID_BASE]._ns_loaded);
1088 main_map->l_phdr = phdr;
1089 main_map->l_phnum = phnum;
1090 main_map->l_entry = *user_entry;
1092 /* At this point we are in a bit of trouble. We would have to
1093 fill in the values for l_dev and l_ino. But in general we
1094 do not know where the file is. We also do not handle AT_EXECFD
1095 even if it would be passed up.
1097 We leave the values here defined to 0. This is normally no
1098 problem as the program code itself is normally no shared
1099 object and therefore cannot be loaded dynamically. Nothing
1100 prevent the use of dynamic binaries and in these situations
1101 we might get problems. We might not be able to find out
1102 whether the object is already loaded. But since there is no
1103 easy way out and because the dynamic binary must also not
1104 have an SONAME we ignore this program for now. If it becomes
1105 a problem we can force people using SONAMEs. */
1107 /* We delay initializing the path structure until we got the dynamic
1108 information for the program. */
1111 main_map->l_map_end = 0;
1112 main_map->l_text_end = 0;
1113 /* Perhaps the executable has no PT_LOAD header entries at all. */
1114 main_map->l_map_start = ~0;
1115 /* And it was opened directly. */
1116 ++main_map->l_direct_opencount;
1118 /* Scan the program header table for the dynamic section. */
1119 for (ph = phdr; ph < &phdr[phnum]; ++ph)
1120 switch (ph->p_type)
1122 case PT_PHDR:
1123 /* Find out the load address. */
1124 main_map->l_addr = (ElfW(Addr)) phdr - ph->p_vaddr;
1125 break;
1126 case PT_DYNAMIC:
1127 /* This tells us where to find the dynamic section,
1128 which tells us everything we need to do. */
1129 main_map->l_ld = (void *) main_map->l_addr + ph->p_vaddr;
1130 break;
1131 case PT_INTERP:
1132 /* This "interpreter segment" was used by the program loader to
1133 find the program interpreter, which is this program itself, the
1134 dynamic linker. We note what name finds us, so that a future
1135 dlopen call or DT_NEEDED entry, for something that wants to link
1136 against the dynamic linker as a shared library, will know that
1137 the shared object is already loaded. */
1138 _dl_rtld_libname.name = ((const char *) main_map->l_addr
1139 + ph->p_vaddr);
1140 /* _dl_rtld_libname.next = NULL; Already zero. */
1141 GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
1143 /* Ordinarilly, we would get additional names for the loader from
1144 our DT_SONAME. This can't happen if we were actually linked as
1145 a static executable (detect this case when we have no DYNAMIC).
1146 If so, assume the filename component of the interpreter path to
1147 be our SONAME, and add it to our name list. */
1148 if (GL(dl_rtld_map).l_ld == NULL)
1150 const char *p = NULL;
1151 const char *cp = _dl_rtld_libname.name;
1153 /* Find the filename part of the path. */
1154 while (*cp != '\0')
1155 if (*cp++ == '/')
1156 p = cp;
1158 if (p != NULL)
1160 _dl_rtld_libname2.name = p;
1161 /* _dl_rtld_libname2.next = NULL; Already zero. */
1162 _dl_rtld_libname.next = &_dl_rtld_libname2;
1166 has_interp = true;
1167 break;
1168 case PT_LOAD:
1170 ElfW(Addr) mapstart;
1171 ElfW(Addr) allocend;
1173 /* Remember where the main program starts in memory. */
1174 mapstart = (main_map->l_addr
1175 + (ph->p_vaddr & ~(GLRO(dl_pagesize) - 1)));
1176 if (main_map->l_map_start > mapstart)
1177 main_map->l_map_start = mapstart;
1179 /* Also where it ends. */
1180 allocend = main_map->l_addr + ph->p_vaddr + ph->p_memsz;
1181 if (main_map->l_map_end < allocend)
1182 main_map->l_map_end = allocend;
1183 if ((ph->p_flags & PF_X) && allocend > main_map->l_text_end)
1184 main_map->l_text_end = allocend;
1186 break;
1188 case PT_TLS:
1189 if (ph->p_memsz > 0)
1191 /* Note that in the case the dynamic linker we duplicate work
1192 here since we read the PT_TLS entry already in
1193 _dl_start_final. But the result is repeatable so do not
1194 check for this special but unimportant case. */
1195 main_map->l_tls_blocksize = ph->p_memsz;
1196 main_map->l_tls_align = ph->p_align;
1197 if (ph->p_align == 0)
1198 main_map->l_tls_firstbyte_offset = 0;
1199 else
1200 main_map->l_tls_firstbyte_offset = (ph->p_vaddr
1201 & (ph->p_align - 1));
1202 main_map->l_tls_initimage_size = ph->p_filesz;
1203 main_map->l_tls_initimage = (void *) ph->p_vaddr;
1205 /* This image gets the ID one. */
1206 GL(dl_tls_max_dtv_idx) = main_map->l_tls_modid = 1;
1208 break;
1210 case PT_GNU_STACK:
1211 GL(dl_stack_flags) = ph->p_flags;
1212 break;
1214 case PT_GNU_RELRO:
1215 main_map->l_relro_addr = ph->p_vaddr;
1216 main_map->l_relro_size = ph->p_memsz;
1217 break;
1220 /* Adjust the address of the TLS initialization image in case
1221 the executable is actually an ET_DYN object. */
1222 if (main_map->l_tls_initimage != NULL)
1223 main_map->l_tls_initimage
1224 = (char *) main_map->l_tls_initimage + main_map->l_addr;
1225 if (! main_map->l_map_end)
1226 main_map->l_map_end = ~0;
1227 if (! main_map->l_text_end)
1228 main_map->l_text_end = ~0;
1229 if (! GL(dl_rtld_map).l_libname && GL(dl_rtld_map).l_name)
1231 /* We were invoked directly, so the program might not have a
1232 PT_INTERP. */
1233 _dl_rtld_libname.name = GL(dl_rtld_map).l_name;
1234 /* _dl_rtld_libname.next = NULL; Already zero. */
1235 GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
1237 else
1238 assert (GL(dl_rtld_map).l_libname); /* How else did we get here? */
1240 /* If the current libname is different from the SONAME, add the
1241 latter as well. */
1242 if (GL(dl_rtld_map).l_info[DT_SONAME] != NULL
1243 && strcmp (GL(dl_rtld_map).l_libname->name,
1244 (const char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
1245 + GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_val) != 0)
1247 static struct libname_list newname;
1248 newname.name = ((char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
1249 + GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_ptr);
1250 newname.next = NULL;
1251 newname.dont_free = 1;
1253 assert (GL(dl_rtld_map).l_libname->next == NULL);
1254 GL(dl_rtld_map).l_libname->next = &newname;
1256 /* The ld.so must be relocated since otherwise loading audit modules
1257 will fail since they reuse the very same ld.so. */
1258 assert (GL(dl_rtld_map).l_relocated);
1260 if (! rtld_is_main)
1262 /* Extract the contents of the dynamic section for easy access. */
1263 elf_get_dynamic_info (main_map, NULL);
1264 /* Set up our cache of pointers into the hash table. */
1265 _dl_setup_hash (main_map);
1268 if (__builtin_expect (mode, normal) == verify)
1270 /* We were called just to verify that this is a dynamic
1271 executable using us as the program interpreter. Exit with an
1272 error if we were not able to load the binary or no interpreter
1273 is specified (i.e., this is no dynamically linked binary. */
1274 if (main_map->l_ld == NULL)
1275 _exit (1);
1277 /* We allow here some platform specific code. */
1278 #ifdef DISTINGUISH_LIB_VERSIONS
1279 DISTINGUISH_LIB_VERSIONS;
1280 #endif
1281 _exit (has_interp ? 0 : 2);
1284 struct link_map **first_preload = &GL(dl_rtld_map).l_next;
1285 #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
1286 /* Set up the data structures for the system-supplied DSO early,
1287 so they can influence _dl_init_paths. */
1288 if (GLRO(dl_sysinfo_dso) != NULL)
1290 /* Do an abridged version of the work _dl_map_object_from_fd would do
1291 to map in the object. It's already mapped and prelinked (and
1292 better be, since it's read-only and so we couldn't relocate it).
1293 We just want our data structures to describe it as if we had just
1294 mapped and relocated it normally. */
1295 struct link_map *l = _dl_new_object ((char *) "", "", lt_library, NULL,
1296 0, LM_ID_BASE);
1297 if (__builtin_expect (l != NULL, 1))
1299 static ElfW(Dyn) dyn_temp[DL_RO_DYN_TEMP_CNT] attribute_relro;
1301 l->l_phdr = ((const void *) GLRO(dl_sysinfo_dso)
1302 + GLRO(dl_sysinfo_dso)->e_phoff);
1303 l->l_phnum = GLRO(dl_sysinfo_dso)->e_phnum;
1304 for (uint_fast16_t i = 0; i < l->l_phnum; ++i)
1306 const ElfW(Phdr) *const ph = &l->l_phdr[i];
1307 if (ph->p_type == PT_DYNAMIC)
1309 l->l_ld = (void *) ph->p_vaddr;
1310 l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn));
1312 else if (ph->p_type == PT_LOAD)
1314 if (! l->l_addr)
1315 l->l_addr = ph->p_vaddr;
1316 if (ph->p_vaddr + ph->p_memsz >= l->l_map_end)
1317 l->l_map_end = ph->p_vaddr + ph->p_memsz;
1318 if ((ph->p_flags & PF_X)
1319 && ph->p_vaddr + ph->p_memsz >= l->l_text_end)
1320 l->l_text_end = ph->p_vaddr + ph->p_memsz;
1322 else
1323 /* There must be no TLS segment. */
1324 assert (ph->p_type != PT_TLS);
1326 l->l_map_start = (ElfW(Addr)) GLRO(dl_sysinfo_dso);
1327 l->l_addr = l->l_map_start - l->l_addr;
1328 l->l_map_end += l->l_addr;
1329 l->l_text_end += l->l_addr;
1330 l->l_ld = (void *) ((ElfW(Addr)) l->l_ld + l->l_addr);
1331 elf_get_dynamic_info (l, dyn_temp);
1332 _dl_setup_hash (l);
1333 l->l_relocated = 1;
1335 /* Initialize l_local_scope to contain just this map. This allows
1336 the use of dl_lookup_symbol_x to resolve symbols within the vdso.
1337 So we create a single entry list pointing to l_real as its only
1338 element */
1339 l->l_local_scope[0]->r_nlist = 1;
1340 l->l_local_scope[0]->r_list = &l->l_real;
1342 /* Now that we have the info handy, use the DSO image's soname
1343 so this object can be looked up by name. Note that we do not
1344 set l_name here. That field gives the file name of the DSO,
1345 and this DSO is not associated with any file. */
1346 if (l->l_info[DT_SONAME] != NULL)
1348 /* Work around a kernel problem. The kernel cannot handle
1349 addresses in the vsyscall DSO pages in writev() calls. */
1350 const char *dsoname = ((char *) D_PTR (l, l_info[DT_STRTAB])
1351 + l->l_info[DT_SONAME]->d_un.d_val);
1352 size_t len = strlen (dsoname);
1353 char *copy = malloc (len);
1354 if (copy == NULL)
1355 _dl_fatal_printf ("out of memory\n");
1356 l->l_libname->name = memcpy (copy, dsoname, len);
1359 /* Rearrange the list so this DSO appears after rtld_map. */
1360 assert (l->l_next == NULL);
1361 assert (l->l_prev == main_map);
1362 GL(dl_rtld_map).l_next = l;
1363 l->l_prev = &GL(dl_rtld_map);
1364 first_preload = &l->l_next;
1366 /* We have a prelinked DSO preloaded by the system. */
1367 GLRO(dl_sysinfo_map) = l;
1368 # ifdef NEED_DL_SYSINFO
1369 if (GLRO(dl_sysinfo) == DL_SYSINFO_DEFAULT)
1370 GLRO(dl_sysinfo) = GLRO(dl_sysinfo_dso)->e_entry + l->l_addr;
1371 # endif
1374 #endif
1376 #ifdef DL_SYSDEP_OSCHECK
1377 DL_SYSDEP_OSCHECK (dl_fatal);
1378 #endif
1380 /* Initialize the data structures for the search paths for shared
1381 objects. */
1382 _dl_init_paths (library_path);
1384 /* Initialize _r_debug. */
1385 struct r_debug *r = _dl_debug_initialize (GL(dl_rtld_map).l_addr,
1386 LM_ID_BASE);
1387 r->r_state = RT_CONSISTENT;
1389 /* Put the link_map for ourselves on the chain so it can be found by
1390 name. Note that at this point the global chain of link maps contains
1391 exactly one element, which is pointed to by dl_loaded. */
1392 if (! GL(dl_rtld_map).l_name)
1393 /* If not invoked directly, the dynamic linker shared object file was
1394 found by the PT_INTERP name. */
1395 GL(dl_rtld_map).l_name = (char *) GL(dl_rtld_map).l_libname->name;
1396 GL(dl_rtld_map).l_type = lt_library;
1397 main_map->l_next = &GL(dl_rtld_map);
1398 GL(dl_rtld_map).l_prev = main_map;
1399 ++GL(dl_ns)[LM_ID_BASE]._ns_nloaded;
1400 ++GL(dl_load_adds);
1402 /* If LD_USE_LOAD_BIAS env variable has not been seen, default
1403 to not using bias for non-prelinked PIEs and libraries
1404 and using it for executables or prelinked PIEs or libraries. */
1405 if (GLRO(dl_use_load_bias) == (ElfW(Addr)) -2)
1406 GLRO(dl_use_load_bias) = main_map->l_addr == 0 ? -1 : 0;
1408 /* Set up the program header information for the dynamic linker
1409 itself. It is needed in the dl_iterate_phdr() callbacks. */
1410 ElfW(Ehdr) *rtld_ehdr = (ElfW(Ehdr) *) GL(dl_rtld_map).l_map_start;
1411 ElfW(Phdr) *rtld_phdr = (ElfW(Phdr) *) (GL(dl_rtld_map).l_map_start
1412 + rtld_ehdr->e_phoff);
1413 GL(dl_rtld_map).l_phdr = rtld_phdr;
1414 GL(dl_rtld_map).l_phnum = rtld_ehdr->e_phnum;
1417 /* PT_GNU_RELRO is usually the last phdr. */
1418 size_t cnt = rtld_ehdr->e_phnum;
1419 while (cnt-- > 0)
1420 if (rtld_phdr[cnt].p_type == PT_GNU_RELRO)
1422 GL(dl_rtld_map).l_relro_addr = rtld_phdr[cnt].p_vaddr;
1423 GL(dl_rtld_map).l_relro_size = rtld_phdr[cnt].p_memsz;
1424 break;
1427 /* Add the dynamic linker to the TLS list if it also uses TLS. */
1428 if (GL(dl_rtld_map).l_tls_blocksize != 0)
1429 /* Assign a module ID. Do this before loading any audit modules. */
1430 GL(dl_rtld_map).l_tls_modid = _dl_next_tls_modid ();
1432 /* If we have auditing DSOs to load, do it now. */
1433 if (__builtin_expect (audit_list != NULL, 0))
1435 /* Iterate over all entries in the list. The order is important. */
1436 struct audit_ifaces *last_audit = NULL;
1437 struct audit_list *al = audit_list->next;
1439 /* Since we start using the auditing DSOs right away we need to
1440 initialize the data structures now. */
1441 tcbp = init_tls ();
1443 /* Initialize security features. We need to do it this early
1444 since otherwise the constructors of the audit libraries will
1445 use different values (especially the pointer guard) and will
1446 fail later on. */
1447 security_init ();
1451 int tls_idx = GL(dl_tls_max_dtv_idx);
1453 /* Now it is time to determine the layout of the static TLS
1454 block and allocate it for the initial thread. Note that we
1455 always allocate the static block, we never defer it even if
1456 no DF_STATIC_TLS bit is set. The reason is that we know
1457 glibc will use the static model. */
1458 struct dlmopen_args dlmargs;
1459 dlmargs.fname = al->name;
1460 dlmargs.map = NULL;
1462 const char *objname;
1463 const char *err_str = NULL;
1464 bool malloced;
1465 (void) _dl_catch_error (&objname, &err_str, &malloced, dlmopen_doit,
1466 &dlmargs);
1467 if (__builtin_expect (err_str != NULL, 0))
1469 not_loaded:
1470 _dl_error_printf ("\
1471 ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
1472 al->name, err_str);
1473 if (malloced)
1474 free ((char *) err_str);
1476 else
1478 struct lookup_args largs;
1479 largs.name = "la_version";
1480 largs.map = dlmargs.map;
1482 /* Check whether the interface version matches. */
1483 (void) _dl_catch_error (&objname, &err_str, &malloced,
1484 lookup_doit, &largs);
1486 unsigned int (*laversion) (unsigned int);
1487 unsigned int lav;
1488 if (err_str == NULL
1489 && (laversion = largs.result) != NULL
1490 && (lav = laversion (LAV_CURRENT)) > 0
1491 && lav <= LAV_CURRENT)
1493 /* Allocate structure for the callback function pointers.
1494 This call can never fail. */
1495 union
1497 struct audit_ifaces ifaces;
1498 #define naudit_ifaces 8
1499 void (*fptr[naudit_ifaces]) (void);
1500 } *newp = malloc (sizeof (*newp));
1502 /* Names of the auditing interfaces. All in one
1503 long string. */
1504 static const char audit_iface_names[] =
1505 "la_activity\0"
1506 "la_objsearch\0"
1507 "la_objopen\0"
1508 "la_preinit\0"
1509 #if __ELF_NATIVE_CLASS == 32
1510 "la_symbind32\0"
1511 #elif __ELF_NATIVE_CLASS == 64
1512 "la_symbind64\0"
1513 #else
1514 # error "__ELF_NATIVE_CLASS must be defined"
1515 #endif
1516 #define STRING(s) __STRING (s)
1517 "la_" STRING (ARCH_LA_PLTENTER) "\0"
1518 "la_" STRING (ARCH_LA_PLTEXIT) "\0"
1519 "la_objclose\0";
1520 unsigned int cnt = 0;
1521 const char *cp = audit_iface_names;
1524 largs.name = cp;
1525 (void) _dl_catch_error (&objname, &err_str, &malloced,
1526 lookup_doit, &largs);
1528 /* Store the pointer. */
1529 if (err_str == NULL && largs.result != NULL)
1531 newp->fptr[cnt] = largs.result;
1533 /* The dynamic linker link map is statically
1534 allocated, initialize the data now. */
1535 GL(dl_rtld_map).l_audit[cnt].cookie
1536 = (intptr_t) &GL(dl_rtld_map);
1538 else
1539 newp->fptr[cnt] = NULL;
1540 ++cnt;
1542 cp = (char *) rawmemchr (cp, '\0') + 1;
1544 while (*cp != '\0');
1545 assert (cnt == naudit_ifaces);
1547 /* Now append the new auditing interface to the list. */
1548 newp->ifaces.next = NULL;
1549 if (last_audit == NULL)
1550 last_audit = GLRO(dl_audit) = &newp->ifaces;
1551 else
1552 last_audit = last_audit->next = &newp->ifaces;
1553 ++GLRO(dl_naudit);
1555 /* Mark the DSO as being used for auditing. */
1556 dlmargs.map->l_auditing = 1;
1558 else
1560 /* We cannot use the DSO, it does not have the
1561 appropriate interfaces or it expects something
1562 more recent. */
1563 #ifndef NDEBUG
1564 Lmid_t ns = dlmargs.map->l_ns;
1565 #endif
1566 _dl_close (dlmargs.map);
1568 /* Make sure the namespace has been cleared entirely. */
1569 assert (GL(dl_ns)[ns]._ns_loaded == NULL);
1570 assert (GL(dl_ns)[ns]._ns_nloaded == 0);
1572 GL(dl_tls_max_dtv_idx) = tls_idx;
1573 goto not_loaded;
1577 al = al->next;
1579 while (al != audit_list->next);
1581 /* If we have any auditing modules, announce that we already
1582 have two objects loaded. */
1583 if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
1585 struct link_map *ls[2] = { main_map, &GL(dl_rtld_map) };
1587 for (unsigned int outer = 0; outer < 2; ++outer)
1589 struct audit_ifaces *afct = GLRO(dl_audit);
1590 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
1592 if (afct->objopen != NULL)
1594 ls[outer]->l_audit[cnt].bindflags
1595 = afct->objopen (ls[outer], LM_ID_BASE,
1596 &ls[outer]->l_audit[cnt].cookie);
1598 ls[outer]->l_audit_any_plt
1599 |= ls[outer]->l_audit[cnt].bindflags != 0;
1602 afct = afct->next;
1608 /* Set up debugging before the debugger is notified for the first time. */
1609 #ifdef ELF_MACHINE_DEBUG_SETUP
1610 /* Some machines (e.g. MIPS) don't use DT_DEBUG in this way. */
1611 ELF_MACHINE_DEBUG_SETUP (main_map, r);
1612 ELF_MACHINE_DEBUG_SETUP (&GL(dl_rtld_map), r);
1613 #else
1614 if (main_map->l_info[DT_DEBUG] != NULL)
1615 /* There is a DT_DEBUG entry in the dynamic section. Fill it in
1616 with the run-time address of the r_debug structure */
1617 main_map->l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r;
1619 /* Fill in the pointer in the dynamic linker's own dynamic section, in
1620 case you run gdb on the dynamic linker directly. */
1621 if (GL(dl_rtld_map).l_info[DT_DEBUG] != NULL)
1622 GL(dl_rtld_map).l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r;
1623 #endif
1625 /* We start adding objects. */
1626 r->r_state = RT_ADD;
1627 _dl_debug_state ();
1629 /* Auditing checkpoint: we are ready to signal that the initial map
1630 is being constructed. */
1631 if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
1633 struct audit_ifaces *afct = GLRO(dl_audit);
1634 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
1636 if (afct->activity != NULL)
1637 afct->activity (&main_map->l_audit[cnt].cookie, LA_ACT_ADD);
1639 afct = afct->next;
1643 /* We have two ways to specify objects to preload: via environment
1644 variable and via the file /etc/ld.so.preload. The latter can also
1645 be used when security is enabled. */
1646 assert (*first_preload == NULL);
1647 struct link_map **preloads = NULL;
1648 unsigned int npreloads = 0;
1650 if (__builtin_expect (preloadlist != NULL, 0))
1652 /* The LD_PRELOAD environment variable gives list of libraries
1653 separated by white space or colons that are loaded before the
1654 executable's dependencies and prepended to the global scope
1655 list. If the binary is running setuid all elements
1656 containing a '/' are ignored since it is insecure. */
1657 char *list = strdupa (preloadlist);
1658 char *p;
1660 HP_TIMING_NOW (start);
1662 /* Prevent optimizing strsep. Speed is not important here. */
1663 while ((p = (strsep) (&list, " :")) != NULL)
1664 if (p[0] != '\0'
1665 && (__builtin_expect (! INTUSE(__libc_enable_secure), 1)
1666 || strchr (p, '/') == NULL))
1667 npreloads += do_preload (p, main_map, "LD_PRELOAD");
1669 HP_TIMING_NOW (stop);
1670 HP_TIMING_DIFF (diff, start, stop);
1671 HP_TIMING_ACCUM_NT (load_time, diff);
1674 /* There usually is no ld.so.preload file, it should only be used
1675 for emergencies and testing. So the open call etc should usually
1676 fail. Using access() on a non-existing file is faster than using
1677 open(). So we do this first. If it succeeds we do almost twice
1678 the work but this does not matter, since it is not for production
1679 use. */
1680 static const char preload_file[] = "/etc/ld.so.preload";
1681 if (__builtin_expect (__access (preload_file, R_OK) == 0, 0))
1683 /* Read the contents of the file. */
1684 file = _dl_sysdep_read_whole_file (preload_file, &file_size,
1685 PROT_READ | PROT_WRITE);
1686 if (__builtin_expect (file != MAP_FAILED, 0))
1688 /* Parse the file. It contains names of libraries to be loaded,
1689 separated by white spaces or `:'. It may also contain
1690 comments introduced by `#'. */
1691 char *problem;
1692 char *runp;
1693 size_t rest;
1695 /* Eliminate comments. */
1696 runp = file;
1697 rest = file_size;
1698 while (rest > 0)
1700 char *comment = memchr (runp, '#', rest);
1701 if (comment == NULL)
1702 break;
1704 rest -= comment - runp;
1706 *comment = ' ';
1707 while (--rest > 0 && *++comment != '\n');
1710 /* We have one problematic case: if we have a name at the end of
1711 the file without a trailing terminating characters, we cannot
1712 place the \0. Handle the case separately. */
1713 if (file[file_size - 1] != ' ' && file[file_size - 1] != '\t'
1714 && file[file_size - 1] != '\n' && file[file_size - 1] != ':')
1716 problem = &file[file_size];
1717 while (problem > file && problem[-1] != ' '
1718 && problem[-1] != '\t'
1719 && problem[-1] != '\n' && problem[-1] != ':')
1720 --problem;
1722 if (problem > file)
1723 problem[-1] = '\0';
1725 else
1727 problem = NULL;
1728 file[file_size - 1] = '\0';
1731 HP_TIMING_NOW (start);
1733 if (file != problem)
1735 char *p;
1736 runp = file;
1737 while ((p = strsep (&runp, ": \t\n")) != NULL)
1738 if (p[0] != '\0')
1739 npreloads += do_preload (p, main_map, preload_file);
1742 if (problem != NULL)
1744 char *p = strndupa (problem, file_size - (problem - file));
1746 npreloads += do_preload (p, main_map, preload_file);
1749 HP_TIMING_NOW (stop);
1750 HP_TIMING_DIFF (diff, start, stop);
1751 HP_TIMING_ACCUM_NT (load_time, diff);
1753 /* We don't need the file anymore. */
1754 __munmap (file, file_size);
1758 if (__builtin_expect (*first_preload != NULL, 0))
1760 /* Set up PRELOADS with a vector of the preloaded libraries. */
1761 struct link_map *l = *first_preload;
1762 preloads = __alloca (npreloads * sizeof preloads[0]);
1763 i = 0;
1766 preloads[i++] = l;
1767 l = l->l_next;
1768 } while (l);
1769 assert (i == npreloads);
1772 /* Load all the libraries specified by DT_NEEDED entries. If LD_PRELOAD
1773 specified some libraries to load, these are inserted before the actual
1774 dependencies in the executable's searchlist for symbol resolution. */
1775 HP_TIMING_NOW (start);
1776 _dl_map_object_deps (main_map, preloads, npreloads, mode == trace, 0);
1777 HP_TIMING_NOW (stop);
1778 HP_TIMING_DIFF (diff, start, stop);
1779 HP_TIMING_ACCUM_NT (load_time, diff);
1781 /* Mark all objects as being in the global scope. */
1782 for (i = main_map->l_searchlist.r_nlist; i > 0; )
1783 main_map->l_searchlist.r_list[--i]->l_global = 1;
1785 #ifndef MAP_ANON
1786 /* We are done mapping things, so close the zero-fill descriptor. */
1787 __close (_dl_zerofd);
1788 _dl_zerofd = -1;
1789 #endif
1791 /* Remove _dl_rtld_map from the chain. */
1792 GL(dl_rtld_map).l_prev->l_next = GL(dl_rtld_map).l_next;
1793 if (GL(dl_rtld_map).l_next != NULL)
1794 GL(dl_rtld_map).l_next->l_prev = GL(dl_rtld_map).l_prev;
1796 for (i = 1; i < main_map->l_searchlist.r_nlist; ++i)
1797 if (main_map->l_searchlist.r_list[i] == &GL(dl_rtld_map))
1798 break;
1800 bool rtld_multiple_ref = false;
1801 if (__builtin_expect (i < main_map->l_searchlist.r_nlist, 1))
1803 /* Some DT_NEEDED entry referred to the interpreter object itself, so
1804 put it back in the list of visible objects. We insert it into the
1805 chain in symbol search order because gdb uses the chain's order as
1806 its symbol search order. */
1807 rtld_multiple_ref = true;
1809 GL(dl_rtld_map).l_prev = main_map->l_searchlist.r_list[i - 1];
1810 if (__builtin_expect (mode, normal) == normal)
1812 GL(dl_rtld_map).l_next = (i + 1 < main_map->l_searchlist.r_nlist
1813 ? main_map->l_searchlist.r_list[i + 1]
1814 : NULL);
1815 #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
1816 if (GLRO(dl_sysinfo_map) != NULL
1817 && GL(dl_rtld_map).l_prev->l_next == GLRO(dl_sysinfo_map)
1818 && GL(dl_rtld_map).l_next != GLRO(dl_sysinfo_map))
1819 GL(dl_rtld_map).l_prev = GLRO(dl_sysinfo_map);
1820 #endif
1822 else
1823 /* In trace mode there might be an invisible object (which we
1824 could not find) after the previous one in the search list.
1825 In this case it doesn't matter much where we put the
1826 interpreter object, so we just initialize the list pointer so
1827 that the assertion below holds. */
1828 GL(dl_rtld_map).l_next = GL(dl_rtld_map).l_prev->l_next;
1830 assert (GL(dl_rtld_map).l_prev->l_next == GL(dl_rtld_map).l_next);
1831 GL(dl_rtld_map).l_prev->l_next = &GL(dl_rtld_map);
1832 if (GL(dl_rtld_map).l_next != NULL)
1834 assert (GL(dl_rtld_map).l_next->l_prev == GL(dl_rtld_map).l_prev);
1835 GL(dl_rtld_map).l_next->l_prev = &GL(dl_rtld_map);
1839 /* Now let us see whether all libraries are available in the
1840 versions we need. */
1842 struct version_check_args args;
1843 args.doexit = mode == normal;
1844 args.dotrace = mode == trace;
1845 _dl_receive_error (print_missing_version, version_check_doit, &args);
1848 /* We do not initialize any of the TLS functionality unless any of the
1849 initial modules uses TLS. This makes dynamic loading of modules with
1850 TLS impossible, but to support it requires either eagerly doing setup
1851 now or lazily doing it later. Doing it now makes us incompatible with
1852 an old kernel that can't perform TLS_INIT_TP, even if no TLS is ever
1853 used. Trying to do it lazily is too hairy to try when there could be
1854 multiple threads (from a non-TLS-using libpthread). */
1855 bool was_tls_init_tp_called = tls_init_tp_called;
1856 if (tcbp == NULL)
1857 tcbp = init_tls ();
1859 if (__builtin_expect (audit_list == NULL, 1))
1860 /* Initialize security features. But only if we have not done it
1861 earlier. */
1862 security_init ();
1864 if (__builtin_expect (mode, normal) != normal)
1866 /* We were run just to list the shared libraries. It is
1867 important that we do this before real relocation, because the
1868 functions we call below for output may no longer work properly
1869 after relocation. */
1870 struct link_map *l;
1872 if (GLRO(dl_debug_mask) & DL_DEBUG_PRELINK)
1874 struct r_scope_elem *scope = &main_map->l_searchlist;
1876 for (i = 0; i < scope->r_nlist; i++)
1878 l = scope->r_list [i];
1879 if (l->l_faked)
1881 _dl_printf ("\t%s => not found\n", l->l_libname->name);
1882 continue;
1884 if (_dl_name_match_p (GLRO(dl_trace_prelink), l))
1885 GLRO(dl_trace_prelink_map) = l;
1886 _dl_printf ("\t%s => %s (0x%0*Zx, 0x%0*Zx)",
1887 l->l_libname->name[0] ? l->l_libname->name
1888 : rtld_progname ?: "<main program>",
1889 l->l_name[0] ? l->l_name
1890 : rtld_progname ?: "<main program>",
1891 (int) sizeof l->l_map_start * 2,
1892 (size_t) l->l_map_start,
1893 (int) sizeof l->l_addr * 2,
1894 (size_t) l->l_addr);
1896 if (l->l_tls_modid)
1897 _dl_printf (" TLS(0x%Zx, 0x%0*Zx)\n", l->l_tls_modid,
1898 (int) sizeof l->l_tls_offset * 2,
1899 (size_t) l->l_tls_offset);
1900 else
1901 _dl_printf ("\n");
1904 else if (GLRO(dl_debug_mask) & DL_DEBUG_UNUSED)
1906 /* Look through the dependencies of the main executable
1907 and determine which of them is not actually
1908 required. */
1909 struct link_map *l = main_map;
1911 /* Relocate the main executable. */
1912 struct relocate_args args = { .l = l, .lazy = GLRO(dl_lazy) };
1913 _dl_receive_error (print_unresolved, relocate_doit, &args);
1915 /* This loop depends on the dependencies of the executable to
1916 correspond in number and order to the DT_NEEDED entries. */
1917 ElfW(Dyn) *dyn = main_map->l_ld;
1918 bool first = true;
1919 while (dyn->d_tag != DT_NULL)
1921 if (dyn->d_tag == DT_NEEDED)
1923 l = l->l_next;
1925 if (!l->l_used)
1927 if (first)
1929 _dl_printf ("Unused direct dependencies:\n");
1930 first = false;
1933 _dl_printf ("\t%s\n", l->l_name);
1937 ++dyn;
1940 _exit (first != true);
1942 else if (! main_map->l_info[DT_NEEDED])
1943 _dl_printf ("\tstatically linked\n");
1944 else
1946 for (l = main_map->l_next; l; l = l->l_next)
1947 if (l->l_faked)
1948 /* The library was not found. */
1949 _dl_printf ("\t%s => not found\n", l->l_libname->name);
1950 else if (strcmp (l->l_libname->name, l->l_name) == 0)
1951 _dl_printf ("\t%s (0x%0*Zx)\n", l->l_libname->name,
1952 (int) sizeof l->l_map_start * 2,
1953 (size_t) l->l_map_start);
1954 else
1955 _dl_printf ("\t%s => %s (0x%0*Zx)\n", l->l_libname->name,
1956 l->l_name, (int) sizeof l->l_map_start * 2,
1957 (size_t) l->l_map_start);
1960 if (__builtin_expect (mode, trace) != trace)
1961 for (i = 1; i < (unsigned int) _dl_argc; ++i)
1963 const ElfW(Sym) *ref = NULL;
1964 ElfW(Addr) loadbase;
1965 lookup_t result;
1967 result = _dl_lookup_symbol_x (INTUSE(_dl_argv)[i], main_map,
1968 &ref, main_map->l_scope,
1969 NULL, ELF_RTYPE_CLASS_PLT,
1970 DL_LOOKUP_ADD_DEPENDENCY, NULL);
1972 loadbase = LOOKUP_VALUE_ADDRESS (result);
1974 _dl_printf ("%s found at 0x%0*Zd in object at 0x%0*Zd\n",
1975 INTUSE(_dl_argv)[i],
1976 (int) sizeof ref->st_value * 2,
1977 (size_t) ref->st_value,
1978 (int) sizeof loadbase * 2, (size_t) loadbase);
1980 else
1982 /* If LD_WARN is set, warn about undefined symbols. */
1983 if (GLRO(dl_lazy) >= 0 && GLRO(dl_verbose))
1985 /* We have to do symbol dependency testing. */
1986 struct relocate_args args;
1987 struct link_map *l;
1989 args.lazy = GLRO(dl_lazy);
1991 l = main_map;
1992 while (l->l_next != NULL)
1993 l = l->l_next;
1996 if (l != &GL(dl_rtld_map) && ! l->l_faked)
1998 args.l = l;
1999 _dl_receive_error (print_unresolved, relocate_doit,
2000 &args);
2002 l = l->l_prev;
2004 while (l != NULL);
2006 if ((GLRO(dl_debug_mask) & DL_DEBUG_PRELINK)
2007 && rtld_multiple_ref)
2009 /* Mark the link map as not yet relocated again. */
2010 GL(dl_rtld_map).l_relocated = 0;
2011 _dl_relocate_object (&GL(dl_rtld_map),
2012 main_map->l_scope, 0, 0);
2015 #define VERNEEDTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERNEED))
2016 if (version_info)
2018 /* Print more information. This means here, print information
2019 about the versions needed. */
2020 int first = 1;
2021 struct link_map *map;
2023 for (map = main_map; map != NULL; map = map->l_next)
2025 const char *strtab;
2026 ElfW(Dyn) *dyn = map->l_info[VERNEEDTAG];
2027 ElfW(Verneed) *ent;
2029 if (dyn == NULL)
2030 continue;
2032 strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
2033 ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr);
2035 if (first)
2037 _dl_printf ("\n\tVersion information:\n");
2038 first = 0;
2041 _dl_printf ("\t%s:\n",
2042 map->l_name[0] ? map->l_name : rtld_progname);
2044 while (1)
2046 ElfW(Vernaux) *aux;
2047 struct link_map *needed;
2049 needed = find_needed (strtab + ent->vn_file);
2050 aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux);
2052 while (1)
2054 const char *fname = NULL;
2056 if (needed != NULL
2057 && match_version (strtab + aux->vna_name,
2058 needed))
2059 fname = needed->l_name;
2061 _dl_printf ("\t\t%s (%s) %s=> %s\n",
2062 strtab + ent->vn_file,
2063 strtab + aux->vna_name,
2064 aux->vna_flags & VER_FLG_WEAK
2065 ? "[WEAK] " : "",
2066 fname ?: "not found");
2068 if (aux->vna_next == 0)
2069 /* No more symbols. */
2070 break;
2072 /* Next symbol. */
2073 aux = (ElfW(Vernaux) *) ((char *) aux
2074 + aux->vna_next);
2077 if (ent->vn_next == 0)
2078 /* No more dependencies. */
2079 break;
2081 /* Next dependency. */
2082 ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next);
2088 _exit (0);
2091 if (main_map->l_info[ADDRIDX (DT_GNU_LIBLIST)]
2092 && ! __builtin_expect (GLRO(dl_profile) != NULL, 0)
2093 && ! __builtin_expect (GLRO(dl_dynamic_weak), 0))
2095 ElfW(Lib) *liblist, *liblistend;
2096 struct link_map **r_list, **r_listend, *l;
2097 const char *strtab = (const void *) D_PTR (main_map, l_info[DT_STRTAB]);
2099 assert (main_map->l_info[VALIDX (DT_GNU_LIBLISTSZ)] != NULL);
2100 liblist = (ElfW(Lib) *)
2101 main_map->l_info[ADDRIDX (DT_GNU_LIBLIST)]->d_un.d_ptr;
2102 liblistend = (ElfW(Lib) *)
2103 ((char *) liblist +
2104 main_map->l_info[VALIDX (DT_GNU_LIBLISTSZ)]->d_un.d_val);
2105 r_list = main_map->l_searchlist.r_list;
2106 r_listend = r_list + main_map->l_searchlist.r_nlist;
2108 for (; r_list < r_listend && liblist < liblistend; r_list++)
2110 l = *r_list;
2112 if (l == main_map)
2113 continue;
2115 /* If the library is not mapped where it should, fail. */
2116 if (l->l_addr)
2117 break;
2119 /* Next, check if checksum matches. */
2120 if (l->l_info [VALIDX(DT_CHECKSUM)] == NULL
2121 || l->l_info [VALIDX(DT_CHECKSUM)]->d_un.d_val
2122 != liblist->l_checksum)
2123 break;
2125 if (l->l_info [VALIDX(DT_GNU_PRELINKED)] == NULL
2126 || l->l_info [VALIDX(DT_GNU_PRELINKED)]->d_un.d_val
2127 != liblist->l_time_stamp)
2128 break;
2130 if (! _dl_name_match_p (strtab + liblist->l_name, l))
2131 break;
2133 ++liblist;
2137 if (r_list == r_listend && liblist == liblistend)
2138 prelinked = true;
2140 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_LIBS, 0))
2141 _dl_debug_printf ("\nprelink checking: %s\n",
2142 prelinked ? "ok" : "failed");
2146 /* Now set up the variable which helps the assembler startup code. */
2147 GL(dl_ns)[LM_ID_BASE]._ns_main_searchlist = &main_map->l_searchlist;
2149 /* Save the information about the original global scope list since
2150 we need it in the memory handling later. */
2151 GLRO(dl_initial_searchlist) = *GL(dl_ns)[LM_ID_BASE]._ns_main_searchlist;
2153 if (prelinked)
2155 if (main_map->l_info [ADDRIDX (DT_GNU_CONFLICT)] != NULL)
2157 ElfW(Rela) *conflict, *conflictend;
2158 #ifndef HP_TIMING_NONAVAIL
2159 hp_timing_t start;
2160 hp_timing_t stop;
2161 #endif
2163 HP_TIMING_NOW (start);
2164 assert (main_map->l_info [VALIDX (DT_GNU_CONFLICTSZ)] != NULL);
2165 conflict = (ElfW(Rela) *)
2166 main_map->l_info [ADDRIDX (DT_GNU_CONFLICT)]->d_un.d_ptr;
2167 conflictend = (ElfW(Rela) *)
2168 ((char *) conflict
2169 + main_map->l_info [VALIDX (DT_GNU_CONFLICTSZ)]->d_un.d_val);
2170 _dl_resolve_conflicts (main_map, conflict, conflictend);
2171 HP_TIMING_NOW (stop);
2172 HP_TIMING_DIFF (relocate_time, start, stop);
2176 /* Mark all the objects so we know they have been already relocated. */
2177 for (struct link_map *l = main_map; l != NULL; l = l->l_next)
2179 l->l_relocated = 1;
2180 if (l->l_relro_size)
2181 _dl_protect_relro (l);
2183 /* Add object to slot information data if necessasy. */
2184 if (l->l_tls_blocksize != 0 && tls_init_tp_called)
2185 _dl_add_to_slotinfo (l);
2188 _dl_sysdep_start_cleanup ();
2190 else
2192 /* Now we have all the objects loaded. Relocate them all except for
2193 the dynamic linker itself. We do this in reverse order so that copy
2194 relocs of earlier objects overwrite the data written by later
2195 objects. We do not re-relocate the dynamic linker itself in this
2196 loop because that could result in the GOT entries for functions we
2197 call being changed, and that would break us. It is safe to relocate
2198 the dynamic linker out of order because it has no copy relocs (we
2199 know that because it is self-contained). */
2201 int consider_profiling = GLRO(dl_profile) != NULL;
2202 #ifndef HP_TIMING_NONAVAIL
2203 hp_timing_t start;
2204 hp_timing_t stop;
2205 #endif
2207 /* If we are profiling we also must do lazy reloaction. */
2208 GLRO(dl_lazy) |= consider_profiling;
2210 struct link_map *l = main_map;
2211 while (l->l_next)
2212 l = l->l_next;
2214 HP_TIMING_NOW (start);
2217 /* While we are at it, help the memory handling a bit. We have to
2218 mark some data structures as allocated with the fake malloc()
2219 implementation in ld.so. */
2220 struct libname_list *lnp = l->l_libname->next;
2222 while (__builtin_expect (lnp != NULL, 0))
2224 lnp->dont_free = 1;
2225 lnp = lnp->next;
2228 if (l != &GL(dl_rtld_map))
2229 _dl_relocate_object (l, l->l_scope, GLRO(dl_lazy),
2230 consider_profiling);
2232 /* Add object to slot information data if necessasy. */
2233 if (l->l_tls_blocksize != 0 && tls_init_tp_called)
2234 _dl_add_to_slotinfo (l);
2236 l = l->l_prev;
2238 while (l);
2239 HP_TIMING_NOW (stop);
2241 HP_TIMING_DIFF (relocate_time, start, stop);
2243 /* Do any necessary cleanups for the startup OS interface code.
2244 We do these now so that no calls are made after rtld re-relocation
2245 which might be resolved to different functions than we expect.
2246 We cannot do this before relocating the other objects because
2247 _dl_relocate_object might need to call `mprotect' for DT_TEXTREL. */
2248 _dl_sysdep_start_cleanup ();
2250 /* Now enable profiling if needed. Like the previous call,
2251 this has to go here because the calls it makes should use the
2252 rtld versions of the functions (particularly calloc()), but it
2253 needs to have _dl_profile_map set up by the relocator. */
2254 if (__builtin_expect (GL(dl_profile_map) != NULL, 0))
2255 /* We must prepare the profiling. */
2256 _dl_start_profile ();
2259 #ifndef NONTLS_INIT_TP
2260 # define NONTLS_INIT_TP do { } while (0)
2261 #endif
2263 if (!was_tls_init_tp_called && GL(dl_tls_max_dtv_idx) > 0)
2264 ++GL(dl_tls_generation);
2266 /* Now that we have completed relocation, the initializer data
2267 for the TLS blocks has its final values and we can copy them
2268 into the main thread's TLS area, which we allocated above. */
2269 _dl_allocate_tls_init (tcbp);
2271 /* And finally install it for the main thread. If ld.so itself uses
2272 TLS we know the thread pointer was initialized earlier. */
2273 if (! tls_init_tp_called)
2275 const char *lossage = TLS_INIT_TP (tcbp, USE___THREAD);
2276 if (__builtin_expect (lossage != NULL, 0))
2277 _dl_fatal_printf ("cannot set up thread-local storage: %s\n",
2278 lossage);
2281 if (! prelinked && rtld_multiple_ref)
2283 /* There was an explicit ref to the dynamic linker as a shared lib.
2284 Re-relocate ourselves with user-controlled symbol definitions.
2286 We must do this after TLS initialization in case after this
2287 re-relocation, we might call a user-supplied function
2288 (e.g. calloc from _dl_relocate_object) that uses TLS data. */
2290 #ifndef HP_TIMING_NONAVAIL
2291 hp_timing_t start;
2292 hp_timing_t stop;
2293 hp_timing_t add;
2294 #endif
2296 HP_TIMING_NOW (start);
2297 /* Mark the link map as not yet relocated again. */
2298 GL(dl_rtld_map).l_relocated = 0;
2299 _dl_relocate_object (&GL(dl_rtld_map), main_map->l_scope, 0, 0);
2300 HP_TIMING_NOW (stop);
2301 HP_TIMING_DIFF (add, start, stop);
2302 HP_TIMING_ACCUM_NT (relocate_time, add);
2305 #ifdef SHARED
2306 /* Auditing checkpoint: we have added all objects. */
2307 if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
2309 struct link_map *head = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
2310 /* Do not call the functions for any auditing object. */
2311 if (head->l_auditing == 0)
2313 struct audit_ifaces *afct = GLRO(dl_audit);
2314 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
2316 if (afct->activity != NULL)
2317 afct->activity (&head->l_audit[cnt].cookie, LA_ACT_CONSISTENT);
2319 afct = afct->next;
2323 #endif
2325 /* Notify the debugger all new objects are now ready to go. We must re-get
2326 the address since by now the variable might be in another object. */
2327 r = _dl_debug_initialize (0, LM_ID_BASE);
2328 r->r_state = RT_CONSISTENT;
2329 _dl_debug_state ();
2331 #ifndef MAP_COPY
2332 /* We must munmap() the cache file. */
2333 _dl_unload_cache ();
2334 #endif
2336 /* Once we return, _dl_sysdep_start will invoke
2337 the DT_INIT functions and then *USER_ENTRY. */
2340 /* This is a little helper function for resolving symbols while
2341 tracing the binary. */
2342 static void
2343 print_unresolved (int errcode __attribute__ ((unused)), const char *objname,
2344 const char *errstring)
2346 if (objname[0] == '\0')
2347 objname = rtld_progname ?: "<main program>";
2348 _dl_error_printf ("%s (%s)\n", errstring, objname);
2351 /* This is a little helper function for resolving symbols while
2352 tracing the binary. */
2353 static void
2354 print_missing_version (int errcode __attribute__ ((unused)),
2355 const char *objname, const char *errstring)
2357 _dl_error_printf ("%s: %s: %s\n", rtld_progname ?: "<program name unknown>",
2358 objname, errstring);
2361 /* Nonzero if any of the debugging options is enabled. */
2362 static int any_debug attribute_relro;
2364 /* Process the string given as the parameter which explains which debugging
2365 options are enabled. */
2366 static void
2367 process_dl_debug (const char *dl_debug)
2369 /* When adding new entries make sure that the maximal length of a name
2370 is correctly handled in the LD_DEBUG_HELP code below. */
2371 static const struct
2373 unsigned char len;
2374 const char name[10];
2375 const char helptext[41];
2376 unsigned short int mask;
2377 } debopts[] =
2379 #define LEN_AND_STR(str) sizeof (str) - 1, str
2380 { LEN_AND_STR ("libs"), "display library search paths",
2381 DL_DEBUG_LIBS | DL_DEBUG_IMPCALLS },
2382 { LEN_AND_STR ("reloc"), "display relocation processing",
2383 DL_DEBUG_RELOC | DL_DEBUG_IMPCALLS },
2384 { LEN_AND_STR ("files"), "display progress for input file",
2385 DL_DEBUG_FILES | DL_DEBUG_IMPCALLS },
2386 { LEN_AND_STR ("symbols"), "display symbol table processing",
2387 DL_DEBUG_SYMBOLS | DL_DEBUG_IMPCALLS },
2388 { LEN_AND_STR ("bindings"), "display information about symbol binding",
2389 DL_DEBUG_BINDINGS | DL_DEBUG_IMPCALLS },
2390 { LEN_AND_STR ("versions"), "display version dependencies",
2391 DL_DEBUG_VERSIONS | DL_DEBUG_IMPCALLS },
2392 { LEN_AND_STR ("all"), "all previous options combined",
2393 DL_DEBUG_LIBS | DL_DEBUG_RELOC | DL_DEBUG_FILES | DL_DEBUG_SYMBOLS
2394 | DL_DEBUG_BINDINGS | DL_DEBUG_VERSIONS | DL_DEBUG_IMPCALLS },
2395 { LEN_AND_STR ("statistics"), "display relocation statistics",
2396 DL_DEBUG_STATISTICS },
2397 { LEN_AND_STR ("unused"), "determined unused DSOs",
2398 DL_DEBUG_UNUSED },
2399 { LEN_AND_STR ("help"), "display this help message and exit",
2400 DL_DEBUG_HELP },
2402 #define ndebopts (sizeof (debopts) / sizeof (debopts[0]))
2404 /* Skip separating white spaces and commas. */
2405 while (*dl_debug != '\0')
2407 if (*dl_debug != ' ' && *dl_debug != ',' && *dl_debug != ':')
2409 size_t cnt;
2410 size_t len = 1;
2412 while (dl_debug[len] != '\0' && dl_debug[len] != ' '
2413 && dl_debug[len] != ',' && dl_debug[len] != ':')
2414 ++len;
2416 for (cnt = 0; cnt < ndebopts; ++cnt)
2417 if (debopts[cnt].len == len
2418 && memcmp (dl_debug, debopts[cnt].name, len) == 0)
2420 GLRO(dl_debug_mask) |= debopts[cnt].mask;
2421 any_debug = 1;
2422 break;
2425 if (cnt == ndebopts)
2427 /* Display a warning and skip everything until next
2428 separator. */
2429 char *copy = strndupa (dl_debug, len);
2430 _dl_error_printf ("\
2431 warning: debug option `%s' unknown; try LD_DEBUG=help\n", copy);
2434 dl_debug += len;
2435 continue;
2438 ++dl_debug;
2441 if (GLRO(dl_debug_mask) & DL_DEBUG_HELP)
2443 size_t cnt;
2445 _dl_printf ("\
2446 Valid options for the LD_DEBUG environment variable are:\n\n");
2448 for (cnt = 0; cnt < ndebopts; ++cnt)
2449 _dl_printf (" %.*s%s%s\n", debopts[cnt].len, debopts[cnt].name,
2450 " " + debopts[cnt].len - 3,
2451 debopts[cnt].helptext);
2453 _dl_printf ("\n\
2454 To direct the debugging output into a file instead of standard output\n\
2455 a filename can be specified using the LD_DEBUG_OUTPUT environment variable.\n");
2456 _exit (0);
2460 static void
2461 process_dl_audit (char *str)
2463 /* The parameter is a colon separated list of DSO names. */
2464 char *p;
2466 while ((p = (strsep) (&str, ":")) != NULL)
2467 if (p[0] != '\0'
2468 && (__builtin_expect (! INTUSE(__libc_enable_secure), 1)
2469 || strchr (p, '/') == NULL))
2471 /* This is using the local malloc, not the system malloc. The
2472 memory can never be freed. */
2473 struct audit_list *newp = malloc (sizeof (*newp));
2474 newp->name = p;
2476 if (audit_list == NULL)
2477 audit_list = newp->next = newp;
2478 else
2480 newp->next = audit_list->next;
2481 audit_list = audit_list->next = newp;
2486 /* Process all environments variables the dynamic linker must recognize.
2487 Since all of them start with `LD_' we are a bit smarter while finding
2488 all the entries. */
2489 extern char **_environ attribute_hidden;
2492 static void
2493 process_envvars (enum mode *modep)
2495 char **runp = _environ;
2496 char *envline;
2497 enum mode mode = normal;
2498 char *debug_output = NULL;
2500 /* This is the default place for profiling data file. */
2501 GLRO(dl_profile_output)
2502 = &"/var/tmp\0/var/profile"[INTUSE(__libc_enable_secure) ? 9 : 0];
2504 while ((envline = _dl_next_ld_env_entry (&runp)) != NULL)
2506 size_t len = 0;
2508 while (envline[len] != '\0' && envline[len] != '=')
2509 ++len;
2511 if (envline[len] != '=')
2512 /* This is a "LD_" variable at the end of the string without
2513 a '=' character. Ignore it since otherwise we will access
2514 invalid memory below. */
2515 continue;
2517 switch (len)
2519 case 4:
2520 /* Warning level, verbose or not. */
2521 if (memcmp (envline, "WARN", 4) == 0)
2522 GLRO(dl_verbose) = envline[5] != '\0';
2523 break;
2525 case 5:
2526 /* Debugging of the dynamic linker? */
2527 if (memcmp (envline, "DEBUG", 5) == 0)
2529 process_dl_debug (&envline[6]);
2530 break;
2532 if (memcmp (envline, "AUDIT", 5) == 0)
2533 process_dl_audit (&envline[6]);
2534 break;
2536 case 7:
2537 /* Print information about versions. */
2538 if (memcmp (envline, "VERBOSE", 7) == 0)
2540 version_info = envline[8] != '\0';
2541 break;
2544 /* List of objects to be preloaded. */
2545 if (memcmp (envline, "PRELOAD", 7) == 0)
2547 preloadlist = &envline[8];
2548 break;
2551 /* Which shared object shall be profiled. */
2552 if (memcmp (envline, "PROFILE", 7) == 0 && envline[8] != '\0')
2553 GLRO(dl_profile) = &envline[8];
2554 break;
2556 case 8:
2557 /* Do we bind early? */
2558 if (memcmp (envline, "BIND_NOW", 8) == 0)
2560 GLRO(dl_lazy) = envline[9] == '\0';
2561 break;
2563 if (memcmp (envline, "BIND_NOT", 8) == 0)
2564 GLRO(dl_bind_not) = envline[9] != '\0';
2565 break;
2567 case 9:
2568 /* Test whether we want to see the content of the auxiliary
2569 array passed up from the kernel. */
2570 if (!INTUSE(__libc_enable_secure)
2571 && memcmp (envline, "SHOW_AUXV", 9) == 0)
2572 _dl_show_auxv ();
2573 break;
2575 case 10:
2576 /* Mask for the important hardware capabilities. */
2577 if (memcmp (envline, "HWCAP_MASK", 10) == 0)
2578 GLRO(dl_hwcap_mask) = __strtoul_internal (&envline[11], NULL,
2579 0, 0);
2580 break;
2582 case 11:
2583 /* Path where the binary is found. */
2584 if (!INTUSE(__libc_enable_secure)
2585 && memcmp (envline, "ORIGIN_PATH", 11) == 0)
2586 GLRO(dl_origin_path) = &envline[12];
2587 break;
2589 case 12:
2590 /* The library search path. */
2591 if (memcmp (envline, "LIBRARY_PATH", 12) == 0)
2593 library_path = &envline[13];
2594 break;
2597 /* Where to place the profiling data file. */
2598 if (memcmp (envline, "DEBUG_OUTPUT", 12) == 0)
2600 debug_output = &envline[13];
2601 break;
2604 if (!INTUSE(__libc_enable_secure)
2605 && memcmp (envline, "DYNAMIC_WEAK", 12) == 0)
2606 GLRO(dl_dynamic_weak) = 1;
2607 break;
2609 case 13:
2610 /* We might have some extra environment variable with length 13
2611 to handle. */
2612 #ifdef EXTRA_LD_ENVVARS_13
2613 EXTRA_LD_ENVVARS_13
2614 #endif
2615 if (!INTUSE(__libc_enable_secure)
2616 && memcmp (envline, "USE_LOAD_BIAS", 13) == 0)
2618 GLRO(dl_use_load_bias) = envline[14] == '1' ? -1 : 0;
2619 break;
2622 if (memcmp (envline, "POINTER_GUARD", 13) == 0)
2623 GLRO(dl_pointer_guard) = envline[14] != '0';
2624 break;
2626 case 14:
2627 /* Where to place the profiling data file. */
2628 if (!INTUSE(__libc_enable_secure)
2629 && memcmp (envline, "PROFILE_OUTPUT", 14) == 0
2630 && envline[15] != '\0')
2631 GLRO(dl_profile_output) = &envline[15];
2632 break;
2634 case 16:
2635 /* The mode of the dynamic linker can be set. */
2636 if (memcmp (envline, "TRACE_PRELINKING", 16) == 0)
2638 mode = trace;
2639 GLRO(dl_verbose) = 1;
2640 GLRO(dl_debug_mask) |= DL_DEBUG_PRELINK;
2641 GLRO(dl_trace_prelink) = &envline[17];
2643 break;
2645 case 20:
2646 /* The mode of the dynamic linker can be set. */
2647 if (memcmp (envline, "TRACE_LOADED_OBJECTS", 20) == 0)
2648 mode = trace;
2649 break;
2651 /* We might have some extra environment variable to handle. This
2652 is tricky due to the pre-processing of the length of the name
2653 in the switch statement here. The code here assumes that added
2654 environment variables have a different length. */
2655 #ifdef EXTRA_LD_ENVVARS
2656 EXTRA_LD_ENVVARS
2657 #endif
2661 /* The caller wants this information. */
2662 *modep = mode;
2664 /* Extra security for SUID binaries. Remove all dangerous environment
2665 variables. */
2666 if (__builtin_expect (INTUSE(__libc_enable_secure), 0))
2668 static const char unsecure_envvars[] =
2669 #ifdef EXTRA_UNSECURE_ENVVARS
2670 EXTRA_UNSECURE_ENVVARS
2671 #endif
2672 UNSECURE_ENVVARS;
2673 const char *nextp;
2675 nextp = unsecure_envvars;
2678 unsetenv (nextp);
2679 /* We could use rawmemchr but this need not be fast. */
2680 nextp = (char *) (strchr) (nextp, '\0') + 1;
2682 while (*nextp != '\0');
2684 if (__access ("/etc/suid-debug", F_OK) != 0)
2686 unsetenv ("MALLOC_CHECK_");
2687 GLRO(dl_debug_mask) = 0;
2690 if (mode != normal)
2691 _exit (5);
2693 /* If we have to run the dynamic linker in debugging mode and the
2694 LD_DEBUG_OUTPUT environment variable is given, we write the debug
2695 messages to this file. */
2696 else if (any_debug && debug_output != NULL)
2698 #ifdef O_NOFOLLOW
2699 const int flags = O_WRONLY | O_APPEND | O_CREAT | O_NOFOLLOW;
2700 #else
2701 const int flags = O_WRONLY | O_APPEND | O_CREAT;
2702 #endif
2703 size_t name_len = strlen (debug_output);
2704 char buf[name_len + 12];
2705 char *startp;
2707 buf[name_len + 11] = '\0';
2708 startp = _itoa (__getpid (), &buf[name_len + 11], 10, 0);
2709 *--startp = '.';
2710 startp = memcpy (startp - name_len, debug_output, name_len);
2712 GLRO(dl_debug_fd) = __open (startp, flags, DEFFILEMODE);
2713 if (GLRO(dl_debug_fd) == -1)
2714 /* We use standard output if opening the file failed. */
2715 GLRO(dl_debug_fd) = STDOUT_FILENO;
2720 /* Print the various times we collected. */
2721 static void
2722 __attribute ((noinline))
2723 print_statistics (hp_timing_t *rtld_total_timep)
2725 #ifndef HP_TIMING_NONAVAIL
2726 char buf[200];
2727 char *cp;
2728 char *wp;
2730 /* Total time rtld used. */
2731 if (HP_TIMING_AVAIL)
2733 HP_TIMING_PRINT (buf, sizeof (buf), *rtld_total_timep);
2734 _dl_debug_printf ("\nruntime linker statistics:\n"
2735 " total startup time in dynamic loader: %s\n", buf);
2737 /* Print relocation statistics. */
2738 char pbuf[30];
2739 HP_TIMING_PRINT (buf, sizeof (buf), relocate_time);
2740 cp = _itoa ((1000ULL * relocate_time) / *rtld_total_timep,
2741 pbuf + sizeof (pbuf), 10, 0);
2742 wp = pbuf;
2743 switch (pbuf + sizeof (pbuf) - cp)
2745 case 3:
2746 *wp++ = *cp++;
2747 case 2:
2748 *wp++ = *cp++;
2749 case 1:
2750 *wp++ = '.';
2751 *wp++ = *cp++;
2753 *wp = '\0';
2754 _dl_debug_printf ("\
2755 time needed for relocation: %s (%s%%)\n", buf, pbuf);
2757 #endif
2759 unsigned long int num_relative_relocations = 0;
2760 for (Lmid_t ns = 0; ns < DL_NNS; ++ns)
2762 if (GL(dl_ns)[ns]._ns_loaded == NULL)
2763 continue;
2765 struct r_scope_elem *scope = &GL(dl_ns)[ns]._ns_loaded->l_searchlist;
2767 for (unsigned int i = 0; i < scope->r_nlist; i++)
2769 struct link_map *l = scope->r_list [i];
2771 if (l->l_addr != 0 && l->l_info[VERSYMIDX (DT_RELCOUNT)])
2772 num_relative_relocations
2773 += l->l_info[VERSYMIDX (DT_RELCOUNT)]->d_un.d_val;
2774 #ifndef ELF_MACHINE_REL_RELATIVE
2775 /* Relative relocations are processed on these architectures if
2776 library is loaded to different address than p_vaddr or
2777 if not prelinked. */
2778 if ((l->l_addr != 0 || !l->l_info[VALIDX(DT_GNU_PRELINKED)])
2779 && l->l_info[VERSYMIDX (DT_RELACOUNT)])
2780 #else
2781 /* On e.g. IA-64 or Alpha, relative relocations are processed
2782 only if library is loaded to different address than p_vaddr. */
2783 if (l->l_addr != 0 && l->l_info[VERSYMIDX (DT_RELACOUNT)])
2784 #endif
2785 num_relative_relocations
2786 += l->l_info[VERSYMIDX (DT_RELACOUNT)]->d_un.d_val;
2790 _dl_debug_printf (" number of relocations: %lu\n"
2791 " number of relocations from cache: %lu\n"
2792 " number of relative relocations: %lu\n",
2793 GL(dl_num_relocations),
2794 GL(dl_num_cache_relocations),
2795 num_relative_relocations);
2797 #ifndef HP_TIMING_NONAVAIL
2798 /* Time spend while loading the object and the dependencies. */
2799 if (HP_TIMING_AVAIL)
2801 char pbuf[30];
2802 HP_TIMING_PRINT (buf, sizeof (buf), load_time);
2803 cp = _itoa ((1000ULL * load_time) / *rtld_total_timep,
2804 pbuf + sizeof (pbuf), 10, 0);
2805 wp = pbuf;
2806 switch (pbuf + sizeof (pbuf) - cp)
2808 case 3:
2809 *wp++ = *cp++;
2810 case 2:
2811 *wp++ = *cp++;
2812 case 1:
2813 *wp++ = '.';
2814 *wp++ = *cp++;
2816 *wp = '\0';
2817 _dl_debug_printf ("\
2818 time needed to load objects: %s (%s%%)\n",
2819 buf, pbuf);
2821 #endif